diff --git a/src/AddIns/Misc/UsageDataCollector/AnalyticsMonitor.cs b/src/AddIns/Misc/UsageDataCollector/AnalyticsMonitor.cs
index 1a75258a00..b1176c7855 100644
--- a/src/AddIns/Misc/UsageDataCollector/AnalyticsMonitor.cs
+++ b/src/AddIns/Misc/UsageDataCollector/AnalyticsMonitor.cs
@@ -27,6 +27,9 @@ namespace ICSharpCode.UsageDataCollector
 			}
 		}
 		
+		/// <summary>
+		/// Allows to enable/disable the usage data monitoring.
+		/// </summary>
 		public static bool Enabled {
 			get {
 				return string.Equals(PropertyService.Get("ICSharpCode.UsageDataCollector.Enabled"), bool.TrueString, StringComparison.OrdinalIgnoreCase);
@@ -52,7 +55,7 @@ namespace ICSharpCode.UsageDataCollector
 		
 		readonly object lockObj = new object();
 		string dbFileName;
-		AnalyticsSessionWriter session;
+		UsageDataSessionWriter session;
 		
 		private AnalyticsMonitor()
 		{
@@ -63,13 +66,17 @@ namespace ICSharpCode.UsageDataCollector
 			SharpDevelop.Gui.WorkbenchSingleton.WorkbenchUnloaded += delegate { CloseSession(); };
 		}
 		
+		/// <summary>
+		/// Opens the database connection, updates the database if required.
+		/// Will start an upload to the server, if required.
+		/// </summary>
 		public void OpenSession()
 		{
 			bool sessionOpened = false;
 			lock (lockObj) {
 				if (session == null) {
 					try {
-						session = new AnalyticsSessionWriter(dbFileName);
+						session = new UsageDataSessionWriter(dbFileName);
 						session.AddEnvironmentData("appVersion", RevisionClass.FullVersion);
 						session.AddEnvironmentData("language", ResourceService.Language);
 						sessionOpened = true;
@@ -79,7 +86,7 @@ namespace ICSharpCode.UsageDataCollector
 							// upgrade database by deleting the old one
 							TryDeleteDatabase();
 							try {
-								session = new AnalyticsSessionWriter(dbFileName);
+								session = new UsageDataSessionWriter(dbFileName);
 							} catch (IncompatibleDatabaseException ex2) {
 								LoggingService.Warn("AnalyticsMonitor: Could upgrade database: " + ex2.Message);
 							}
@@ -95,6 +102,11 @@ namespace ICSharpCode.UsageDataCollector
 			}
 		}
 		
+		/// <summary>
+		/// Retrieves all stored data as XML text.
+		/// </summary>
+		/// <exception cref="IncompatibleDatabaseException">The database version is not compatible with this
+		/// version of the AnalyticsSessionWriter.</exception>
 		public string GetTextForStoredData()
 		{
 			UsageDataUploader uploader = new UsageDataUploader(dbFileName);
diff --git a/src/AddIns/Misc/UsageDataCollector/UsageDataMessage.cs b/src/AddIns/Misc/UsageDataCollector/UsageDataMessage.cs
index a639de2c40..c67520149d 100644
--- a/src/AddIns/Misc/UsageDataCollector/UsageDataMessage.cs
+++ b/src/AddIns/Misc/UsageDataCollector/UsageDataMessage.cs
@@ -11,9 +11,16 @@ using System.Runtime.Serialization;
 
 namespace ICSharpCode.UsageDataCollector
 {
+	/// <summary>
+	/// Represents a message used to send data to the server.
+	/// </summary>
 	[DataContract]
 	sealed class UsageDataMessage
 	{
+		/// <summary>
+		/// Unique identifier per user.
+		/// We need this to distinguish between 1 user using a feature 100 times, or 100 users using a feature 1 time.
+		/// </summary>
 		[DataMember]
 		public Guid UserID;
 		
@@ -33,12 +40,23 @@ namespace ICSharpCode.UsageDataCollector
 	[DataContract]
 	sealed class UsageDataSession
 	{
+		/// <summary>
+		/// ID of the session, usually unique per user (unless the user restores a backup of the database).
+		/// Could be used to detect duplicate uploads.
+		/// </summary>
 		[DataMember]
 		public long SessionID;
 		
+		/// <summary>
+		/// Timestamp when the session was started.
+		/// </summary>
 		[DataMember]
 		public DateTime StartTime;
 		
+		/// <summary>
+		/// Timestamp when the session finished.
+		/// Nullable because the end time might not be recorded if the application crashed.
+		/// </summary>
 		[DataMember]
 		public DateTime? EndTime;
 		
@@ -52,6 +70,11 @@ namespace ICSharpCode.UsageDataCollector
 		public List<UsageDataException> Exceptions = new List<UsageDataException>();
 	}
 	
+	/// <summary>
+	/// A property storing a value about the environment (App version, OS Version etc.).
+	/// These are stored per session because the user might use different versions of an application in parallel,
+	/// or have multiple OS installations pointing to the same database (e.g. when SharpDevelop is used on an USB stick).
+	/// </summary>
 	[DataContract]
 	sealed class UsageDataEnvironmentProperty
 	{
@@ -62,31 +85,62 @@ namespace ICSharpCode.UsageDataCollector
 		public string Value;
 	}
 	
+	/// <summary>
+	/// Represents a feature being used.
+	/// </summary>
 	[DataContract]
 	sealed class UsageDataFeatureUse
 	{
+		/// <summary>
+		/// The time when the feature was used.
+		/// </summary>
 		[DataMember]
 		public DateTime Time;
 		
+		/// <summary>
+		/// End time of the feature use. Nullable because for some features, the no time span will be recorded.
+		/// Also, for features where the time span usually is recorded, crashes might cause the end time to be missing
+		/// in some cases.
+		/// </summary>
 		[DataMember]
 		public DateTime? EndTime;
 		
+		/// <summary>
+		/// Name of the feature.
+		/// </summary>
 		[DataMember]
 		public string FeatureName;
 		
+		/// <summary>
+		/// How the feature was activated (Menu, Toolbar, Shortcut, etc.)
+		/// </summary>
 		[DataMember]
 		public string ActivationMethod;
 	}
 	
+	/// <summary>
+	/// Represents an exception that was recorded.
+	/// Only ExceptionType and StackTrace are available because those don't contain personal information.
+	/// The exception message might e.g. contain names of the file the user is working on.
+	/// </summary>
 	[DataContract]
 	sealed class UsageDataException
 	{
+		/// <summary>
+		/// The time when the exception occurred.
+		/// </summary>
 		[DataMember]
 		public DateTime Time;
 		
+		/// <summary>
+		/// The fully qualified typename of the exception.
+		/// </summary>
 		[DataMember]
 		public string ExceptionType;
 		
+		/// <summary>
+		/// The stack trace of the exception. The 'at'/'in' words are potentially localized.
+		/// </summary>
 		[DataMember]
 		public string StackTrace;
 	}
diff --git a/src/AddIns/Misc/UsageDataCollector/UsageDataSessionWriter.cs b/src/AddIns/Misc/UsageDataCollector/UsageDataSessionWriter.cs
index e0d56b4746..6844e59829 100644
--- a/src/AddIns/Misc/UsageDataCollector/UsageDataSessionWriter.cs
+++ b/src/AddIns/Misc/UsageDataCollector/UsageDataSessionWriter.cs
@@ -12,9 +12,13 @@ using System.Runtime.Serialization;
 namespace ICSharpCode.UsageDataCollector
 {
 	/// <summary>
-	/// Creates an analytics session.
+	/// Creates a usage data session.
+	/// 
+	/// Instance methods on this class are not thread-safe. If you are using it in a multi-threaded application,
+	/// you should consider writing your own wrapper class that takes care of the thread-safety.
+	/// In SharpDevelop, this is done by the AnalyticsMonitor class.
 	/// </summary>
-	public class AnalyticsSessionWriter : IDisposable
+	public class UsageDataSessionWriter : IDisposable
 	{
 		SQLiteConnection connection;
 		long sessionID;
@@ -22,8 +26,9 @@ namespace ICSharpCode.UsageDataCollector
 		/// <summary>
 		/// Opens/Creates the database and starts writing a new session to it.
 		/// </summary>
-		/// <exception cref="IncompatibleDatabaseException"></exception>
-		public AnalyticsSessionWriter(string databaseFileName)
+		/// <exception cref="IncompatibleDatabaseException">The database version is not compatible with this
+		/// version of the AnalyticsSessionWriter.</exception>
+		public UsageDataSessionWriter(string databaseFileName)
 		{
 			SQLiteConnectionStringBuilder conn = new SQLiteConnectionStringBuilder();
 			conn.Add("Data Source", databaseFileName);
@@ -129,6 +134,11 @@ namespace ICSharpCode.UsageDataCollector
 			}
 		}
 		
+		/// <summary>
+		/// Adds environment data to the current session.
+		/// </summary>
+		/// <param name="name">Name of the data entry.</param>
+		/// <param name="value">Value of the data entry.</param>
 		public void AddEnvironmentData(string name, string value)
 		{
 			using (SQLiteCommand cmd = this.connection.CreateCommand()) {
@@ -141,6 +151,12 @@ namespace ICSharpCode.UsageDataCollector
 			}
 		}
 		
+		/// <summary>
+		/// Adds a feature use to the session.
+		/// </summary>
+		/// <param name="featureName">Name of the feature.</param>
+		/// <param name="activationMethod">How the feature was activated (Menu, Toolbar, Shortcut, etc.)</param>
+		/// <returns>ID that can be used for <see cref="WriteEndTimeForFeature"/></returns>
 		public long AddFeatureUse(string featureName, string activationMethod)
 		{
 			long featureRowId;
@@ -160,15 +176,24 @@ namespace ICSharpCode.UsageDataCollector
 			return featureRowId;
 		}
 		
-		public void WriteEndTimeForFeature(long featureID)
+		/// <summary>
+		/// Marks the end time for a feature use.
+		/// </summary>
+		/// <param name="featureUseID">A value returned from <see cref="AddFeatureUse"/>.</param>
+		public void WriteEndTimeForFeature(long featureUseID)
 		{
 			using (SQLiteCommand cmd = this.connection.CreateCommand()) {
 				cmd.CommandText = "UPDATE FeatureUses SET endTime = datetime('now') WHERE id = ?;";
-				cmd.Parameters.Add(new SQLiteParameter { Value = featureID });
+				cmd.Parameters.Add(new SQLiteParameter { Value = featureUseID });
 				cmd.ExecuteNonQuery();
 			}
 		}
 		
+		/// <summary>
+		/// Adds an exception report to the session.
+		/// </summary>
+		/// <param name="exceptionType">Full .NET type name of the exception.</param>
+		/// <param name="stacktrace">Stacktrace</param>
 		public void AddException(string exceptionType, string stacktrace)
 		{
 			using (SQLiteCommand cmd = this.connection.CreateCommand()) {
@@ -181,10 +206,18 @@ namespace ICSharpCode.UsageDataCollector
 			}
 		}
 		
+		bool isDisposed;
+		
+		/// <summary>
+		/// Closes the session.
+		/// </summary>
 		public void Dispose()
 		{
-			EndSession();
-			connection.Close();
+			if (!isDisposed) {
+				isDisposed = true;
+				EndSession();
+				connection.Dispose();
+			}
 		}
 	}
 	
diff --git a/src/AddIns/Misc/UsageDataCollector/UsageDataUploader.cs b/src/AddIns/Misc/UsageDataCollector/UsageDataUploader.cs
index 813c344187..887107bec5 100644
--- a/src/AddIns/Misc/UsageDataCollector/UsageDataUploader.cs
+++ b/src/AddIns/Misc/UsageDataCollector/UsageDataUploader.cs
@@ -24,6 +24,9 @@ namespace ICSharpCode.UsageDataCollector
 	{
 		string databaseFileName;
 		
+		/// <summary>
+		/// Creates a new UsageDataUploader.
+		/// </summary>
 		public UsageDataUploader(string databaseFileName)
 		{
 			this.databaseFileName = databaseFileName;
@@ -38,6 +41,11 @@ namespace ICSharpCode.UsageDataCollector
 			return connection;
 		}
 		
+		/// <summary>
+		/// Retrieves all stored data as XML text.
+		/// </summary>
+		/// <exception cref="IncompatibleDatabaseException">The database version is not compatible with this
+		/// version of the AnalyticsSessionWriter.</exception>
 		public string GetTextForStoredData()
 		{
 			UsageDataMessage message;
@@ -60,6 +68,8 @@ namespace ICSharpCode.UsageDataCollector
 		/// <summary>
 		/// Starts the upload of the usage data.
 		/// </summary>
+		/// <exception cref="IncompatibleDatabaseException">The database version is not compatible with this
+		/// version of the AnalyticsSessionWriter.</exception>
 		public void StartUpload()
 		{
 			UsageDataMessage message;