I find it hard to imagine that sort of system working well on MO. People have started using meta for announcements, which I think is just fine.

An announcement is almost the exact opposite of a question. Even in your original proposal, you seem to suggest that questions and announcements would essentially be two completely separate parts of the site, so your imagining can't been too different from mine. If the "announcements part" of the site is going to be essentially disjoint from the "questions part", why not just make a separate site and use an engine that's better for announcements? Responses to announcements would be much more like a conversation than an answer, so sorting things by votes and limiting to 600 character comments is absurd. If you're announcing a reading group or learning seminar, it would make sense for people to be able to easily express interest, agree on a schedule, and take responsibility for bits of a text. All these things would be at best clumsy on MO, and would seem out of place.

If Google Wave improves, I think it would be nice to have an announcements wave for this purpose. The feature set is much more amicable to the sort of use you're describing. It's also much easier to set up a wave than to set up a website. To illustrate, I've made a Math Announcements wave. (If you don't have a wave account, email me; I've got a bunch of invitations.)

Of course, the problem is that for an announcements page to do any good, people actually have to look at it. Presumably the idea was to bootstrap an announcements page using the MO community. I think that part still makes sense, but you need to start with something. If somebody makes a nice announcements site/wave, gets a few dozen people using it and gets some content up so that it actually looks like it's going to work, I'd be happy to link to it in the FAQ and even post a system message on MO encouraging people to check it out. I'm sure many math blogs would also link to it, but it needs some steam behind it to begin with, and I think there needs to be a person or handful of people making sure it runs smoothly.

Thank you for your elaboration. I am reminded of a line from Louie DePalma in the TV sitcom Taxi. It goes something like this: "You wrecked a taxi to avoid hitting a dog? Now if you wanted to avoid hitting your grandmother, I'd understand. I wouldn't agree, but I'd understand. But a dog?"

I still think there are various aspects of announcements and requests for seminars that are very similar to what is going on at MO, so I disagree. Making sure that this forum does one job very well is something I understand.

Gerhard "Ask Me About System Design" Paseman, 2010.03.24