Yeah, inertia. What we've tried to do with IMPP is to roll all of the features that IM users actually want into the core protocol versus just saying "it's open

Yeah, inertia. What we've tried to do with IMPP is to roll all of the features that IM users actually want into the core protocol versus just saying "it's open!" or "it can be extended!" and hoping someone else does the dirty work. We build the server side and we build the client side, which is important; it means we're not off dreaming up pie-in-the-sky features that would be absolutely horrible for a client developer to implemement. We have some experience reverse engineering the rest of the IM protocols out there as well, and they all have their own issues which we kept in mind when building ours. At the end of the day, our actual motivations were simple: publishing the protocol is the right thing to do and so we did it. It's been on our TODO for 6+ years. :)