I think Plurk should have stayed quiet for a few days and let Microsoft negotiate with them privately. Clearly one doesn't want to just let Microsoft off the hook, but there's a decent potential that Microsoft would be willing to pay private, non-disclosed reparations or even license the technology or buy the firm. Once the initial problem is fixed (and that has happened), one can quiet down a little and not create further hostility in the hopes that a good, mutually-beneficial outcome will happen.

Microsoft didn't fight and didn't try to use its market position once they found out what happened and, while that doesn't abdicate one of responsibility, it does mean that you can deal with them a bit more in good faith. Granted, that's easy for me to say - it wasn't my work that was ripped off and so I'm not as emotionally involved as the Plurk people who are probably (rightfully so) angry.