Olark - Real-time chat and monitoring of your website visitors through Google Talk and Jabber.
TeamViewer - TeamViewer lets you establish a connection to any PC or server within just a few seconds.
LiveChat - LiveChat - premium live chat software. Approach customers directly on the website, make connections and drive more sales using LiveChat.
mRemoteNG - mRemoteNG is a fork of mRemote, an open source, tabbed, multi-protocol, remote connections manager.
Intercom - Intercom is a customer relationship management and messaging tool for web businesses. Build relationships with users to create loyal customers.
join.me - Instant screen sharing. Instant Aha!