Single secure login, invisilibity support, voice and video messaging, new protocol...
New in 4.x:
Single secure login for all accounts, new "open, secure, flexible, and efficient protocol"; styled and formatted messaging features; typing notifications; full invisibility support; offline messaging (with timestamped messages); file transfer support (including server proxying); Astra Flash-based profile integration; directly-integrated voice and video messaging; easy inline image transfer; drawing support; Buzz support; ability to sign on from multiple locations; Release Notes - Last Updated: 11.13.09 (v4.0.0.118 / v4.1.0.16 Beta Release)
Upgrade Meter:5
New in 3.1.x: Support for multiple identities via the new Identities & Connections Manager, feature for preventing accidental contact list merging, ability to edit AIM profiles in HTML via new Biography section, speed and usability improvements; Release Notes - Last Updated: 08.04.09 (v3.1.13.0)
Upgrade Meter:4
New in 3.0: Redesigned interface, various other enhancements and bug fixes for earlier releases - Last Updated: 12.20.04
Pros: Free basic edition (with no ads or spyware components), interoperable with most major IM networks, skinnable for the décor-minded, simplifies adding new buddies and services, readily available tech help
Cons: Development of basic edition takes a backseat to the commercial Pro version, doesn't support as many IM networks as Gaim, interoperability means even more IMs than before
