I'm looking for a secure, private IM service or use at work, very much like TeamTalk or Bopup, but I also need a web-based interface as well as apps on both iOS and Android mobile devices. TeamTalk only has a Windows and Mac client.
Private chat, group chat, offline messaging and conversation history logging are the primary features I'm looking for, but TeamTalk goes beyond and also offers file transfer, screen sharing and capture. Those would be nice features to have.
I'm not completely convinced about Jabber, but I'm willing to give it a chance.
Since we're using for work, it doesn't need to be free, but we're a small team, so the price should be reasonable!