I actually think keeping such postings in the main section will work better, because it pressures posters to publicize in a manner and frequency that news.yc readers will like.
If you accompany each update of, for example, squeezed books, with a learning from the last time you posted, then people will vote it up.
I posted here asking for feedback with my site twice, fifteen days apart, and nobody questioned whether I should do this. I think news.yc is inclusive as is.
I wouldn't want to see a lot of updates. Much more than one a month I think I would find irritating, especially as more people join the site. A "hey, I am publishing this" notice is cool, perhaps something else for major accomplishments or news, but beyond that I wouldn't want to have a lot of "hey, I just added RSS for comments!" type of announcements.
One of the things about having a tab is that the launch announcements would stick around there a little bit longer.
Why not do it both ways - in the main area and then have a startup site area, maybe using a tag. I think the convenience of having all the new startup sites in one area for people to explore would be great. Generically, having some kind of tags for categories here would be a great advance, such as "VC's" "Angels" "Programming" "UI" "Startups" etc etc.
Thought crossed my mind: a lot of people have sites or startups they would like to publicize once or twice. Perhaps that could get its own category? You could have a karma-cutoff to keep out spammers.
Perhaps this would also make the site feel that much more 'inclusive' of those who aren't in the YC program (and may have no intentions of attempting to participate), which was a request a while back.
I won't bother linking to all the previous times I've requested you add guidance text to the submissions page, including pointing them to the Feature Requests thread. I'm sure you've seen them yet prefer to leave the page sparse.
Is it intended as some kind of intelligence test on your users? In the same way as not explaining the markup system anywhere? If so, I think it's a silly test, and one your users are happy to fail.
If you haven't got the time to concoct some text, here's a suggestion:
Submit a URL with a well-thought through title to explain its relevance to your audience. Leaving the URL empty will submit a question for discussion. Please ensure submissions are relevant to Startup News; if you want Slashdot, Digg, or Reddit, you know where to find them. There's a thread for Feature Requests, so please add a post to that and refrain from starting anymore "Vote up for ..." threads. There's a bookmarklet to ease submitting, but it doesn't mean these guidelines don't apply.
If you accompany each update of, for example, squeezed books, with a learning from the last time you posted, then people will vote it up.
I posted here asking for feedback with my site twice, fifteen days apart, and nobody questioned whether I should do this. I think news.yc is inclusive as is.