I've worked really hard over the past few months to get the word out. I have a really active blog, and that helps a lot. Most of the interest has come through the blog. Leaving thoughtful comments on big blogs, twitter, and attending open coffees. It all adds up. Rather than focus on the big things, I've just spent a lot of time doing little things to build the buzz. I don't think it's our private alpha users - they would not be connected to VCs. Most VCs have said they stumbled across my blog or the site and liked the vision.
Just sent you an alpha invite.