The Trillian IM chat client is available on top platforms, including Windows, OS X, iOS, and Android. Beyond its interoperability with all the important IM networks, Trillian offers social integration with Facebook, Twitter and LinkedIn. One notable feature of Trillian is its "continuous chat" capability, which lets you pick up a conversation from a different device without missing out important snippets. The searchable message history viewer makes sifting through prior conversations a snap. Trillian is free, though a paid version offers an ad-free experience.