Aside from Sqwiggle, which I hadn't heard of but hate on sight, this sounds remarkably similar to my team's workflow. I'm not certain whether idonethis would offer enough benefit to be worthwhile compared to simple daily emails to a team mailing list, filtered into a label (or folder for non-gmail folks) though.

Actually, we use Hangouts a bit differently too. We don't really have a concept of 'at work' vs 'not at work'. When I'm working, I am, by definition, busy. It's often more convenient for me to receive a chat when I'm not working - watching TV or whatever. Plus, I have Hangouts on my phone, so I'm very rarely unreachable, unless I'm sleeping. The distinction therefore shifts from at work/not at work to available/busy. If I'm available I'll answer a chat immediately; if I'm busy I won't, unless it's particularly important. Also, each member of our team works whatever hours are most convenient for them, which often don't overlap much, so it's beneficial that we're available when necessary to answer quick questions even when we're not in work mode. (Not that we need to often, since asynchronous methods of communication usually tend to do the trick.)

It's similar to one of the many objections I had to Sqwiggle: this idea that since I'm sitting at my desk, it's therefore a good time to contact me. Often the exact opposite is true: http://www.paulgraham.com/makersschedule.html