A number of changes to v0.5.0 end up breaking a whole bunch of plugins. But the good news is after v0.5.0, we'll enter a non-breaking-change phase where successive patch versions (v0.5.1, 0.5.2, etc) will not break compatibility... or we'll try not to, rather.
Compatibility notes should be standard in all plugins, but it's still early. We're moving from minver to compatibility, so that should cover all cases, and allow the package manager to show only plugins approved for installation.
While not exactly spam, there in certainly the chance one user will harass another via the chat system. I presume setting urself as offline would make you unavailable for chat in some-way, but that's not exactly helpful in that situation.
Are chat logs private?
Can Admins view the logs?
Can chat be selectively disabled for users or groups?
What features exist for chat atm? (as of 0.3.2)