We liked the prospects for Geni , David Sacks' nifty family tree builder, when it came out. I was impressed that my father, who struggles with the internet, would spend a couple of hours filling in the names of obscure Yorkshire relatives. But I haven't been back to the site since, and I suspect that's true of many other early users. Geni's takeoff, so striking that one was inclined to believe even the erratic Alexa charts , has been followed by a sickening plunge. There's no reason, yet, for users to return. Charles River Ventures' decision to lead a round, at a reported $100m valuation , says more about partner George Zachary's previously documented eagerness for deals, and Sacks' Paypal pedigree , than it does about Geni's more modest prospects.