[vasco]

We use discourse for this. Any type of forum-like product is very effective as a complement to email and instant messages for the reasons you describe. For effective remote I think it's indispensable to have: Instant messaging, email, forum, wiki. Looks like p2 might also serve as a sort of "company directory" thing, which we also use another product for, but I don't get much as value out of that.

[twic]

In 2000 I worked at a company that used an NNTP server for an internal forum. Back then it was common for mail clients to speak NNTP, so you could flip back and forth between correspondence and discussion in the same tool, easily reply to or forward posts by email, etc. That was the smoothest and most productive application of this idea I've seen.

[noahtallen]

I think in my mind, P2 fulfills both email and forum roles internally. But it does have a high level of integration with our other internal tools.