Ask HN: How do you stay in touch with your team?

I work for a fairly decent-sized company, and the inter-team-communication tools like Hipchat all seem to really stink security-wise. What does the greater HN world use? XMPP? IRC?

I know Microsoft uses their own internal thing (as does Google), but for a company that's spread over 2+ offices, are there any good communication services out there?