There are various rumors that eBay is trying to sell StumbleUpon. As TechCrunch notes, within the year their traffic has decreased from 31 million pageviews/month to 25 million pageviews/month and from 4.4 million visitors to 1.3 million. Not a good return on their investment.
Like the Skype acquisition, I never understood the investment thesis behind StumbleUpon. How did they expect this to build more community around eBay? Or push people to purchase product? What synergy did they see with these acquisitions? I should ask people at eBay that I know, but it's water under the bridge now.