We're running MS Communicator, with an upgrade to Lync in pre-deployment trials. I confess to not 'getting' this tool. Specifically, I don't know when to use it, what situations make IM or chat preferable to e-mail or even (gods forbid) a phone call. We're a multinational company, and the only advantage I can see is that using Communicator for a voice call saves the costs of an international long-distance telephone call. However, it's configured only for internal use; outside communications must still go through e-mail, telephone, etc.

I don't avoid or ignore it, I can handle the mechanics of using it, and I respond when someone else uses the tool to initiate a conversation. I just don't know why I'd pick it over the tools I'm accustomed to. I'm not mobile, so that doesn't factor into my usage.