I think the biggest useful thing Y Combinator provides is the marketing/publicity at the start. As someone else mentioned, many online blogs will write about yo

I think the biggest useful thing Y Combinator provides is the marketing/publicity at the start. As someone else mentioned, many online blogs will write about you, as you are a y combinator startup. Also I see a tendency of other yc startups promoting other startups (like justin.tv clickpass, disqus clickpass, etc...)