compact, portable instant messaging
Download from PortableApps.com
Miranda NG 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 NG is a multi protocol instant messenger client for Windows. Miranda NG uses very little memory and is extremely fast. It supports ICQ, AIM, MSN, Jabber, Yahoo, IRC and more. Functionality can be greatly enhanced with an extensive set of plugins including Skype and more. The interface and setup is a bit more involved than some other IM clients, but the customization options available are richer.