diff --git a/src/categories.js b/src/categories.js
index 0e47e7b1a8..2049b22c99 100644
--- a/src/categories.js
+++ b/src/categories.js
@@ -171,8 +171,14 @@ var db = require('./database'),
 
 	Categories.isTopicsRead = function(cid, uid, callback) {
 		db.getSortedSetRange('categories:' + cid + ':tid', 0, -1, function(err, tids) {
+			if(err) {
+				return callback(err);
+			}
 
-			topics.hasReadTopics(tids, uid, function(hasRead) {
+			topics.hasReadTopics(tids, uid, function(err, hasRead) {
+				if(err) {
+					return callback(err);
+				}
 
 				var allread = true;
 				for (var i = 0, ii = tids.length; i < ii; i++) {
@@ -271,8 +277,6 @@ var db = require('./database'),
 		});
 	};
 
-
-
 	Categories.getCategoryData = function(cid, callback) {
 		db.exists('category:' + cid, function(err, exists) {
 			if (exists) {
diff --git a/src/database/mongo.js b/src/database/mongo.js
index e3a5d3529c..63338856f6 100644
--- a/src/database/mongo.js
+++ b/src/database/mongo.js
@@ -424,10 +424,23 @@
 	// sets
 
 	module.setAdd = function(key, value, callback) {
-		if(value !== null && value !== undefined) {
-			value = value.toString();
+		if(!Array.isArray(value)) {
+			value = [value];
 		}
-		db.collection('objects').update({_key:key}, {$addToSet: { members: value }}, {upsert:true, w: 1},  function(err, result) {
+
+		value.forEach(function(element, index, array) {
+			array[index] = element ? element.toString() : element;
+		});
+
+
+		db.collection('objects').update({_key:key},
+			{
+				$addToSet: { members: { $each: value } }
+			},
+			{
+				upsert:true, w: 1
+			}
+		, function(err, result) {
 			if(typeof callback === 'function') {
 				callback(err, result);
 			}
@@ -435,10 +448,15 @@
 	}
 
 	module.setRemove = function(key, value, callback) {
-		if(value !== null && value !== undefined) {
-			value = value.toString();
+		if(!Array.isArray(value)) {
+			value = [value];
 		}
-		db.collection('objects').update({_key:key, members: value}, {$pull : {members: value}}, function(err, result) {
+
+		value.forEach(function(element, index, array) {
+			array[index] = element ? element.toString() : element;
+		});
+
+		db.collection('objects').update( { _key: key }, { $pullAll: { members: value } }, function(err, result) {
 			if(typeof callback === 'function') {
 				callback(err, result);
 			}
@@ -456,17 +474,26 @@
 	}
 
 	module.isMemberOfSets = function(sets, value, callback) {
-		function iterator(set, next) {
-			module.isSetMember(set, value, function(err, result) {
-				if(err) {
-					return next(err);
-				}
 
-				next(null, result?1:0);
-			});
+		if(value !== null && value !== undefined) {
+			value = value.toString();
 		}
 
-		async.map(sets, iterator, callback);
+		db.collection('objects').find({_key: {$in : sets}, members: value}).toArray(function(err, result) {
+			if(err) {
+				return callback(err);
+			}
+
+			result = result.map(function(item) {
+				return item._key;
+			});
+
+			result = sets.map(function(set) {
+				return result.indexOf(set) !== -1 ? 1 : 0;
+			});
+
+			callback(err, result);
+		});
 	}
 
 	module.getSetMembers = function(key, callback) {
@@ -655,16 +682,18 @@
 		if(value !== null && value !== undefined) {
 			value = value.toString();
 		}
-		module.getSortedSetRange(key, 0, -1, function(err, result) {
+		module.getSortedSetRevRange(key, 0, -1, function(err, result) {
 			if(err) {
 				return callback(err);
 			}
+
 			var rank = result.indexOf(value);
+
 			if(rank === -1) {
 				return callback(null, null);
 			}
 
-			callback(null, result.length - rank - 1);
+			callback(null, rank);
 		});
 	}
 
diff --git a/src/meta.js b/src/meta.js
index d95614b082..fd344b460e 100644
--- a/src/meta.js
+++ b/src/meta.js
@@ -243,7 +243,7 @@ var fs = require('fs'),
 		minFile: path.join(__dirname, '..', 'public/src/nodebb.min.js'),
 		get: function (callback) {
 			plugins.fireHook('filter:scripts.get', this.scripts, function(err, scripts) {
-				var mtime,
+				var ctime,
 					jsPaths = scripts.map(function (jsPath) {
 						jsPath = path.normalize(jsPath);
 
@@ -267,12 +267,12 @@ var fs = require('fs'),
 
 				if (process.env.NODE_ENV !== 'development') {
 					async.parallel({
-						mtime: function (next) {
+						ctime: function (next) {
 							async.map(jsPaths, fs.stat, function (err, stats) {
 								async.reduce(stats, 0, function (memo, item, next) {
 									if(item) {
-										mtime = +new Date(item.mtime);
-										next(null, mtime > memo ? mtime : memo);
+										ctime = +new Date(item.ctime);
+										next(null, ctime > memo ? ctime : memo);
 									} else {
 										next(null, memo);
 									}
@@ -286,14 +286,15 @@ var fs = require('fs'),
 							}
 
 							fs.stat(Meta.js.minFile, function (err, stat) {
-								next(err, +new Date(stat.mtime));
+								next(err, +new Date(stat.ctime));
 							});
 						}
 					}, function (err, results) {
-						if (results.minFile > results.mtime) {
+						if (results.minFile > results.ctime) {
 							winston.info('No changes to client-side libraries -- skipping minification');
 							callback(null, [path.relative(path.join(__dirname, '../public'), Meta.js.minFile)]);
 						} else {
+							winston.info('Minifying client-side libraries -- please wait');
 							Meta.js.minify(function () {
 								callback(null, [
 									path.relative(path.join(__dirname, '../public'), Meta.js.minFile)
diff --git a/src/plugins.js b/src/plugins.js
index 9614777524..93806a8a9a 100644
--- a/src/plugins.js
+++ b/src/plugins.js
@@ -71,7 +71,7 @@ var fs = require('fs'),
 					plugins.push(meta.config['theme:id']);
 
 					async.each(plugins, function(plugin, next) {
-						if (!plugin) {
+						if (!plugin || typeof plugin !== 'string') {
 							return next();
 						}
 
@@ -377,7 +377,7 @@ var fs = require('fs'),
 					}).filter(function(file) {
 						var stats = fs.statSync(file),
 							isPlugin =  file.substr(npmPluginPath.length + 1, 14) === 'nodebb-plugin-' || file.substr(npmPluginPath.length + 1, 14) === 'nodebb-widget-';
-							
+
 						if (stats.isDirectory() && isPlugin) return true;
 						else return false;
 					});
diff --git a/src/topics.js b/src/topics.js
index bdcd055526..6ad23bee70 100644
--- a/src/topics.js
+++ b/src/topics.js
@@ -518,8 +518,10 @@ var async = require('async'),
 						return callback(null);
 					}
 
-					Topics.hasReadTopics(tids, uid, function(read) {
-
+					Topics.hasReadTopics(tids, uid, function(err, read) {
+						if(err) {
+							return callback(err);
+						}
 						var newtids = tids.filter(function(tid, index, self) {
 							return read[index] === 0;
 						});
@@ -563,8 +565,10 @@ var async = require('async'),
 					unreadTids.push.apply(unreadTids, tids);
 					callback(null);
 				} else {
-					Topics.hasReadTopics(tids, uid, function(read) {
-
+					Topics.hasReadTopics(tids, uid, function(err, read) {
+						if(err) {
+							return callback(err);
+						}
 						var newtids = tids.filter(function(tid, index, self) {
 							return parseInt(read[index], 10) === 0;
 						});
@@ -572,11 +576,7 @@ var async = require('async'),
 
 						async.filter(newtids, function(tid, next) {
 							threadTools.privileges(tid, uid, function(err, privileges) {
-								if (!err && privileges.read) {
-									next(true);
-								} else {
-									next(false);
-								}
+								next(!err && privileges.read);
 							});
 						}, function(newtids) {
 							unreadTids.push.apply(unreadTids, newtids);
@@ -692,9 +692,7 @@ var async = require('async'),
 			}
 
 			function hasReadTopic(next) {
-				Topics.hasReadTopic(topicData.tid, current_user, function(hasRead) {
-					next(null, hasRead);
-				});
+				Topics.hasReadTopic(topicData.tid, current_user, next);
 			}
 
 			function getTeaserInfo(next) {
@@ -870,9 +868,7 @@ var async = require('async'),
 
 		function getReadStatus(next) {
 			if (uid && parseInt(uid, 10) > 0) {
-				Topics.hasReadTopic(tid, uid, function(read) {
-					next(null, read);
-				});
+				Topics.hasReadTopic(tid, uid, next);
 			} else {
 				next(null, null);
 			}
@@ -989,7 +985,7 @@ var async = require('async'),
 
 	Topics.hasReadTopics = function(tids, uid, callback) {
 		if(!parseInt(uid, 10)) {
-			return callback(tids.map(function() {
+			return callback(null, tids.map(function() {
 				return false;
 			}));
 		}
@@ -1000,25 +996,15 @@ var async = require('async'),
 			sets.push('tid:' + tids[i] + ':read_by_uid');
 		}
 
-		db.isMemberOfSets(sets, uid, function(err, hasRead) {
-			callback(hasRead);
-		});
+		db.isMemberOfSets(sets, uid, callback);
 	};
 
 	Topics.hasReadTopic = function(tid, uid, callback) {
 		if(!parseInt(uid, 10)) {
-			return callback(false);
+			return callback(null, false);
 		}
 
-		db.isSetMember('tid:' + tid + ':read_by_uid', uid, function(err, hasRead) {
-
-			if (err === null) {
-				callback(hasRead);
-			} else {
-				console.log(err);
-				callback(false);
-			}
-		});
+		db.isSetMember('tid:' + tid + ':read_by_uid', uid, callback);
 	};
 
 	Topics.getTeasers = function(tids, callback) {
diff --git a/src/user.js b/src/user.js
index 1a048c9d73..39f0befef9 100644
--- a/src/user.js
+++ b/src/user.js
@@ -1136,8 +1136,9 @@ var bcrypt = require('bcryptjs'),
 				async.filter(nids, function(nid, next) {
 					notifications.get(nid, uid, function(notifObj) {
 						if(!notifObj) {
-							next(false);
+							return next(false);
 						}
+
 						if (notifObj.uniqueId === uniqueId) {
 							next(true);
 						} else {