multi-protocol chat client
Download from PortableApps.com
Miranda IM Portable can run from a cloud folder, external drive, or local folder without installing into Windows. It's even better with the PortableApps.com Platform for easy installs and automatic updates.
Miranda IM is a multi protocol instant messenger client for Windows. Miranda IM uses very little memory and is extremely fast. It supports ICQ, Jabber, Yahoo, IRC and more. Functionality can be greatly enhanced with an extensive set of plugins (currently over 350) as well. The interface and setup is a bit more involved than other IM clients like Pidgin Portable, but the customization options available are richer.