[DaFranker]

The key: Whatever works for you.™ Each team's needs will vary.

But that's probably not very helpful. By "for programmers", I assume you want something that can be relatively unobtrusive when needed, that keeps conversation logs, and that can be linked up / hacked with for whatever particular tricks you need. And by "for small teams", I assume you mean you want something that can handle chat rooms with joining and leaving of users at any time. Maybe you even want it to remember and show what other users discussed while you were gone.

For this, the most common de facto choice is Hangouts. Other software, some embedded in larger software solutions, is also used with varying degrees of satisfaction. My personal favorite is Slack(1), and it seems to be gaining popularity quickly. Other (relatively known) examples include Campfire(2), Atlassian's HipChat(3), FlowDock(4), and so on.

A google search for variations on the theme "team collaboration chat", mixing up the keywords "realtime" and "logs" and "persistent" as needed, can bring up more options than you have time to try. Pick a few that seem to do what you need and try them out.

[1] https://slack.com/ [2] https://campfirenow.com/ [3] https://www.atlassian.com/software/hipchat/ [4] https://www.flowdock.com/