We’re at the Web 2.0 Summit in San Francisco, sitting on the floor in a room packed with people here to see Mark Zuckerberg kick off a strong first-day lineup. The Facebook CEO basically just admitted to the much-discussed Facebook $15 billion valuation financing, telling interviewer John Battelle: “It’s going well, we’ve almost wrapped things up.” Battelle was taken aback by the lack of “no comment,” and pressed his luck by noting that the meteoric valuation is “a lot.”

Zuckerberg’s coy, but informative response? “We’ll see.”

We’ll keep you posted.

A couple other quick bits, from responses to audience questions:

Question: Will you allow users to export their data?

Zuckerberg: We want to get there. We realize that this is a flaw within the system now and something we want to get out.

Question: What are the pros and cons of taking additional investment?

Zuckerberg: Taking money allows you to accelerate growth, it allows you to look at other opportunities that you wouldn’t have. Also, there are the standard cons as well.

Moving on, Marissa Mayer from Google (GOOG) comes on and theorizes about all sorts of things, both joking and serious, that Google could do in the health space. She says sharing health information with family and friends and sending x-rays around, for instance, might be things the company will address.

Anssi Vanjoki of Nokia (NOK) then talks about the handset maker’s new N810, a Linux-based tablet. He also pontificates on a context-aware Internet enabled by GPS.