diff --git a/core/boot.js b/core/boot.js
index b8f2c4b5e..1b3df9aec 100644
--- a/core/boot.js
+++ b/core/boot.js
@@ -2,11 +2,9 @@
 title: $:/core/boot.js
 type: application/javascript
 
-The main boot kernel for TiddlyWiki. This single file creates a barebones TW environment that is just
-sufficient to bootstrap the modules containing the main logic of the application.
+The main boot kernel for TiddlyWiki. This single file creates a barebones TW environment that is just sufficient to bootstrap the modules containing the main logic of the application.
 
-On the server this file is executed directly to boot TiddlyWiki. In the browser, this file is packed
-into a single HTML file along with other elements:
+On the server this file is executed directly to boot TiddlyWiki. In the browser, this file is packed into a single HTML file along with other elements:
 
 # bootprefix.js
 # <module definitions>
@@ -83,7 +81,7 @@ $tw.plugins = {};
 // Modules store registers all the modules the system has seen
 $tw.modules = $tw.modules || {};
 $tw.modules.titles = $tw.modules.titles || {}; // hashmap by module title of {fn:, exports:, moduleType:}
-$tw.modules.types = $tw.modules.types || {}; // hashmap by module type of array of exports
+$tw.modules.types = $tw.modules.types || {}; // hashmap by module type of hashmap of exports
 
 // Config object
 $tw.config = $tw.config || {};
@@ -300,9 +298,28 @@ Register the exports of a single module in the $tw.modules.types hashmap
 */
 $tw.modules.registerModuleExports = function(name,moduleType,moduleExports) {
 	if(!$tw.utils.hop($tw.modules.types,moduleType)) {
-		$tw.modules.types[moduleType] = [];
+		$tw.modules.types[moduleType] = {};
+	}
+	if($tw.utils.hop($tw.modules.types[moduleType],name)) {
+		console.log("Warning: Reregistering module - " + name);
+	}
+	$tw.modules.types[moduleType][name] = moduleExports;
+};
+
+/*
+Apply a callback to each module of a particular type
+	moduleType: type of modules to enumerate
+	callback: function called as callback(title,moduleExports) for each module
+*/
+$tw.modules.forEachModuleOfType = function(moduleType,callback) {
+	var modules = $tw.modules.types[moduleType];
+	if(modules) {
+		for(var title in modules) {
+			if($tw.utils.hop(modules,title)) {
+				callback(title,modules[title]);
+			}
+		}
 	}
-	$tw.modules.types[moduleType].push(moduleExports);
 };
 
 /*
@@ -310,13 +327,10 @@ Get all the modules of a particular type in a hashmap by their `name` field
 */
 $tw.modules.getModulesByTypeAsHashmap = function(moduleType,nameField) {
 	nameField = nameField || "name";
-	var modules = $tw.modules.types[moduleType],
-		results = {};
-	if(modules) {
-		for(var t=0; t<modules.length; t++) {
-			results[modules[t][nameField]] =  modules[t];
-		}
-	}
+	var results = {};
+	$tw.modules.forEachModuleOfType(moduleType,function(title,module) {
+		results[module[nameField]] = module;
+	});
 	return results;
 };
 
@@ -324,16 +338,13 @@ $tw.modules.getModulesByTypeAsHashmap = function(moduleType,nameField) {
 Apply the exports of the modules of a particular type to a target object
 */
 $tw.modules.applyMethods = function(moduleType,object) {
-	var modules = $tw.modules.types[moduleType],
-		n,m,f;
-	if(modules) {
-		for(n=0; n<modules.length; n++) {
-			m = modules[n];
-			for(f in m) {
-				object[f] = m[f];
+	$tw.modules.forEachModuleOfType(moduleType,function(title,module) {
+		for(var field in module) {
+			if($tw.utils.hop(module,field)) {
+				object[field] = module[field];
 			}
 		}
-	}
+	});
 };
 
 /////////////////////////// Barebones tiddler object
@@ -775,7 +786,7 @@ Load the tiddlers from a bundle folder, and package them up into a proper JSON b
 */
 $tw.loadBundleFolder = function(filepath,excludeRegExp) {
 	excludeRegExp = excludeRegExp || /^\.DS_Store$|.meta$/;
-	var stat, files, bundleInfo = {tiddlers: []}, bundleTiddlers = [], f, file, titlePrefix, t;
+	var stat, files, bundleInfo, bundleTiddlers = [], f, file, titlePrefix, t;
 	if(fs.existsSync(filepath)) {
 		stat = fs.statSync(filepath);
 		if(stat.isDirectory()) {
@@ -803,12 +814,12 @@ $tw.loadBundleFolder = function(filepath,excludeRegExp) {
 		}
 	}
 	// Save the bundle tiddler
-	return {
+	return bundleInfo ? {
 		title: bundleInfo.title,
 		type: "application/json",
 		bundle: "yes",
 		text: JSON.stringify(bundleInfo)
-	};
+	} : null;
 };
 
 /*
@@ -879,20 +890,33 @@ if($tw.browser) {
 	// On the server, we load tiddlers from specified folders
 	var folders = [
 		$tw.boot.bootPath,
-		path.resolve($tw.boot.wikiPath,$tw.config.wikiPluginsSubDir),
 		path.resolve($tw.boot.wikiPath,$tw.config.wikiShadowsSubDir),
 		path.resolve($tw.boot.wikiPath,$tw.config.wikiTiddlersSubDir)
 	];
 	for(t=0; t<folders.length; t++) {
 		$tw.wiki.addTiddlers($tw.loadTiddlersFromPath(folders[t]));
 	}
-	// Load any plugins specified within the wiki folder
+	// Load any plugins listed in the wiki info file
 	var wikiInfoPath = path.resolve($tw.boot.wikiPath,$tw.config.wikiInfo);
 	if(fs.existsSync(wikiInfoPath)) {
 		var wikiInfo = JSON.parse(fs.readFileSync(wikiInfoPath,"utf8")),
 			pluginBasePath = path.resolve($tw.boot.bootPath,$tw.config.pluginsPath);
 		for(t=0; t<wikiInfo.plugins.length; t++) {
-			$tw.wiki.addTiddler($tw.loadBundleFolder(path.resolve(pluginBasePath,"./" + wikiInfo.plugins[t])));
+			var bundle = $tw.loadBundleFolder(path.resolve(pluginBasePath,"./" + wikiInfo.plugins[t]));
+			if(bundle) {
+				$tw.wiki.addTiddler(bundle);
+			}
+		}
+	}
+	// Load any plugins within the wiki folder
+	var wikiPluginsPath = path.resolve($tw.boot.wikiPath,$tw.config.wikiPluginsSubDir);
+	if(fs.existsSync(wikiPluginsPath)) {
+		var pluginFolders = fs.readdirSync(wikiPluginsPath);
+		for(t=0; t<pluginFolders.length; t++) {
+			var bundle = $tw.loadBundleFolder(path.resolve(wikiPluginsPath,"./" + pluginFolders[t]));
+			if(bundle) {
+				$tw.wiki.addTiddler(bundle);
+			}
 		}
 	}
 }
@@ -904,9 +928,10 @@ $tw.wiki.unpackBundleTiddlers();
 $tw.wiki.registerModuleTiddlers();
 
 // Run any startup modules
-var mainModules = $tw.modules.types.startup;
-for(var m=0; m<mainModules.length; m++) {
-	mainModules[m].startup();
-}
+$tw.modules.forEachModuleOfType("startup",function(title,module) {
+	if(module.startup) {
+		module.startup();
+	}
+});
 
 })();
diff --git a/core/bootprefix.js b/core/bootprefix.js
index 49d4f9abf..e313b14ec 100644
--- a/core/bootprefix.js
+++ b/core/bootprefix.js
@@ -26,6 +26,9 @@ Define a JavaScript tiddler module for later execution
 	fn: function defining the module, called with the arguments (module,require,exports)
 */
 $tw.modules.define = function(moduleName,moduleType,fn) {
+	if(Object.prototype.hasOwnProperty.call($tw.modules.titles,moduleName)) {
+		console.log("Warning: Redefined module - " + moduleName);
+	}
 	$tw.modules.titles[moduleName] = {
 		moduleType: moduleType,
 		fn: fn
diff --git a/core/modules/commander.js b/core/modules/commander.js
index 6378a40da..17cc04db4 100644
--- a/core/modules/commander.js
+++ b/core/modules/commander.js
@@ -93,23 +93,17 @@ Commander.prototype.executeNextCommand = function() {
 };
 
 Commander.initCommands = function(moduleType) {
-	// Install the command modules
 	moduleType = moduleType || "command";
 	$tw.commands = {};
-	var modules = $tw.modules.types[moduleType],
-		n,m,f,c;
-	if(modules) {
-		for(n=0; n<modules.length; n++) {
-			m = modules[n];
-			$tw.commands[m.info.name] = {};
-			c = $tw.commands[m.info.name];
-			// Add the methods defined by the module
-			for(f in m) {
-				c[f] = m[f];
+	$tw.modules.forEachModuleOfType(moduleType,function(title,module) {
+		var c = $tw.commands[module.info.name] = {};
+		// Add the methods defined by the module
+		for(var f in module) {
+			if($tw.utils.hop(module,f)) {
+				c[f] = module[f];
 			}
 		}
-	}
-
+	});
 };
 
 exports.Commander = Commander;
diff --git a/core/modules/parsers/newwikitextparser/newwikitextparser.js b/core/modules/parsers/newwikitextparser/newwikitextparser.js
index 4bdb67036..d96f3bc88 100644
--- a/core/modules/parsers/newwikitextparser/newwikitextparser.js
+++ b/core/modules/parsers/newwikitextparser/newwikitextparser.js
@@ -266,17 +266,17 @@ var WikiTextParser = function(options) {
 	this.runRules = [];
 	var blockRegExpStrings = [],
 		runRegExpStrings = [],
-		rules = ($tw.modules.types.wikitextrule || []).slice(0);
-	for(var t=0; t<rules.length; t++) {
-		if(rules[t].blockParser) {
-			this.blockRules.push(rules[t]);
-			blockRegExpStrings.push("(" + rules[t].regExpString + ")");
+		self = this;
+	$tw.modules.forEachModuleOfType("wikitextrule",function(title,module) {
+		if(module.blockParser) {
+			self.blockRules.push(module);
+			blockRegExpStrings.push("(" + module.regExpString + ")");
 		}
-		if(rules[t].runParser) {
-			this.runRules.push(rules[t]);
-			runRegExpStrings.push("(" + rules[t].regExpString + ")");
+		if(module.runParser) {
+			self.runRules.push(module);
+			runRegExpStrings.push("(" + module.regExpString + ")");
 		}
-	}
+	});
 	this.blockRegExp = new RegExp(blockRegExpStrings.join("|"),"mg");
 	this.runRegExp = new RegExp(runRegExpStrings.join("|"),"mg");
 };
diff --git a/core/modules/startup.js b/core/modules/startup.js
index 88c625985..26fad35c6 100644
--- a/core/modules/startup.js
+++ b/core/modules/startup.js
@@ -42,12 +42,11 @@ exports.startup = function() {
 	// Host-specific startup
 	if($tw.browser) {
 		// Call browser startup modules
-		modules = $tw.modules.types["browser-startup"];
-		if(modules) {
-			for(m=0; m<modules.length; m++) {
-				modules[m].startup();
+		$tw.modules.forEachModuleOfType("browser-startup",function(title,module) {
+			if(module.startup) {
+				module.startup();
 			}
-		}
+		});
 		// Install the popup manager
 		$tw.popup = new $tw.utils.Popup({
 			wiki: $tw.wiki,
@@ -113,7 +112,6 @@ exports.startup = function() {
 			{output: process.stdout, error: process.stderr}
 		);
 		commander.execute();
-
 	}
 
 };
diff --git a/core/modules/wiki.js b/core/modules/wiki.js
index fa4e34b59..083040a57 100644
--- a/core/modules/wiki.js
+++ b/core/modules/wiki.js
@@ -387,21 +387,18 @@ exports.clearCache = function(title) {
 exports.initParsers = function(moduleType) {
 	// Install the parser modules
 	moduleType = moduleType || "parser";
-	$tw.wiki.parsers = {}; 
-	var modules = $tw.modules.types[moduleType],
-		n,m,f;
-	if(modules) {
-		for(n=0; n<modules.length; n++) {
-			m = modules[n];
-			// Add the parsers defined by the module
-			for(f in m) {
-				$tw.wiki.parsers[f] = new m[f]({wiki: this}); // Store an instance of the parser
+	$tw.wiki.parsers = {};
+	var self = this;
+	$tw.modules.forEachModuleOfType(moduleType,function(title,module) {
+		for(var f in module) {
+			if($tw.utils.hop(module,f)) {
+				$tw.wiki.parsers[f] = new module[f]({wiki: self}); // Store an instance of the parser
 			}
 		}
-	}
+	});
 	// Install the rules for the old wikitext parser rules
 	var wikitextparser = this.parsers["text/x-tiddlywiki-old"];
-	if(modules && wikitextparser) {
+	if(wikitextparser) {
 		wikitextparser.installRules();
 	}
 };
@@ -501,10 +498,8 @@ It's useful to remember what the `new` keyword does. It:
 */
 exports.initMacros = function(moduleType) {
 	moduleType = moduleType || "macro";
-	$tw.wiki.macros = {}; 
+	$tw.wiki.macros = {};
 	var MacroClass = require("./treenodes/macro.js").Macro,
-		modules = $tw.modules.types[moduleType],
-		n,m,f,
 		subclassMacro = function(module) {
 			// Make a copy of the Macro() constructor function
 			var MacroMaker = function Macro() {
@@ -514,17 +509,16 @@ exports.initMacros = function(moduleType) {
 			MacroMaker.prototype = new MacroClass();
 			// Add the prototype methods for this instance of the macro
 			for(var f in module) {
-				MacroMaker.prototype[f] = module[f];
+				if($tw.utils.hop(module,f)) {
+					MacroMaker.prototype[f] = module[f];
+				}
 			}
 			// Make a more convenient reference to the macro info
 			return MacroMaker;
 		};
-	if(modules) {
-		for(n=0; n<modules.length; n++) {
-			m = modules[n];
-			$tw.wiki.macros[m.info.name] = subclassMacro(m);
-		}
-	}
+	$tw.modules.forEachModuleOfType(moduleType,function(title,module) {
+		$tw.wiki.macros[module.info.name] = subclassMacro(module);
+	});
 };
 
 /*
@@ -582,12 +576,12 @@ exports.initSavers = function(moduleType) {
 	moduleType = moduleType || "saver";
 	// Instantiate the available savers
 	this.savers = [];
-	for(var t=0; t<$tw.modules.types[moduleType].length; t++) {
-		var saver = $tw.modules.types[moduleType][t];
-		if(saver.canSave(this)) {
-			this.savers.push(saver.create(this));
+	var self = this;
+	$tw.modules.forEachModuleOfType(moduleType,function(title,module) {
+		if(module.canSave(self)) {
+			self.savers.push(module.create(self));
 		}
-	}
+	});
 	// Sort the savers into priority order
 	this.savers.sort(function(a,b) {
 		if(a.info.priority < b.info.priority) {
diff --git a/plugins/tiddlywiki/dropbox/dropbox.js b/plugins/tiddlywiki/dropbox/dropbox.js
index ae1743ec0..843ff96ed 100644
--- a/plugins/tiddlywiki/dropbox/dropbox.js
+++ b/plugins/tiddlywiki/dropbox/dropbox.js
@@ -88,10 +88,9 @@ $tw.plugins.dropbox.login = function() {
 Invoke any dropbox-startup modules
 */
 $tw.plugins.dropbox.invokeDropboxStartupModules = function(loggedIn) {
-	var mods = $tw.modules.types["dropbox-startup"];
-	for(var m=0; m<mods.length; m++) {
-		mods[m].startup(loggedIn);
-	}
+	$tw.modules.forEachModuleOfType("dropbox-startup",function(title,module) {
+		module.startup(loggedIn);
+	});
 };
 
 /*
diff --git a/tw5.com/plugins/demoplugin/demoplugin.js b/tw5.com/plugins/demoplugin/demoplugin.js
deleted file mode 100644
index 386695799..000000000
--- a/tw5.com/plugins/demoplugin/demoplugin.js
+++ /dev/null
@@ -1,15 +0,0 @@
-/*\
-title: $:/tiddlywiki/plugins/demoplugin/demoplugin.js
-type: application/javascript
-module-type: demo
-
-A demo plugin
-
-\*/
-(function(){
-
-/*jslint node: true, browser: true */
-"use strict";
-
-
-})();