In the six months since its acquisition for $75 million by EBAY, StumbleUpon membership has nearly doubled to 4 million, according to EBAY, which posted news of the milestone on its official blog today.

The site is a video recommendation platform organized by members, or "stumblers," who suggest videos to others with similar interests.

In September, I interviewed StumbleUpon founder Garrett Camp, 28, on the campus of MIT where he was being honored as one of the world’s top young innovators.  (I reposted this clip  today.)

He told me how StumpleUpon is gaining revenue by serving sponsored pages into queries.  Not sure how the revenue model is working out, but he is certainly building scale.   

Off-camera he told me that working with EBAY was terrific and supportive, but his company remains operationally separate — and is still based in San Francisco.  I asked the young Canadian if he might just cash out from the EBAY windfall and buy a giant ranch up in his native Alberta.  He said no, he loves what he’s doing.  Congrats Garrett on your success.

You can find the embed code for my interview right here.

— Andy Plesser