Last week, StumbleUpon announced it was buying itself out of its much-vaunted previous corporate buyout, by being born again as an “investor-baked start-up.”

The Canadian-born social-bookmarking company, which was launched earlier, had come to the Bay area in 2006 and got some fancy angel investors, who ponied up a couple of million dollars. It soon became a traffic-generating hit.

Then, StumbleUpon was bought by eBay (EBAY) two years ago for $75 million in one of Web 2.0’s high points.

End of a fairy tale? Um, nope.

Soon enough, due to both buyers’ and sellers’ remorse, rumors of the San Francisco-based company being sold by its new owners swirled around it, although there was no sale.

Instead, last week, StumbleUpon announced that a roster of well-known Silicon Valley investors, including Ram Shriram of Sherpalo Ventures, Accel Partners and August Capital, would return it to its roots.

Its founders, Garrett Camp and Geoff Smith were included, with Camp as CEO.

In a video interview he did with BoomTown, here’s Camp talking all about the latest shift for his start-up, including discussing some more changes on the site, such as an even more personalized Webification of the content discovery service.

Here’s the video:

The content-discovery service, StumbleUpon, has gotten itself back to start-up status, after being bought by eBay two years ago.

It announced today that it was returning to being an “investor-backed startup” by a roster of well-known Silicon Valley investors, including Ram Shriram of Sherpalo Ventures, Accel Partners and August Capital.

Its founders, Garrett Camp and Geoff Smith are also back, with Camp now in place as CEO.

“We are grateful to eBay for its guidance. However, we realized there were few long-term synergies between the two businesses. It is best for us to part ways and focus on our respective strengths,” said Camp, stating the very obvious.

That’s quite a boomerang since it was acquired by the auction giant in 2007 for $75 million.

Before that event, which was at the height of the Web 2.0 fervor, the Canadian-born social-bookmarking start-up, which launched several years ago, came to the Bay area in 2006 and got some fancy venture investors (Mitch Kapor, Ron Conway, Shriram and others) who ponied up a couple of million dollars. It soon became a traffic-generating hit.

But rumors of the San Francisco-based company being sold by eBay (EBAY) have swirled around it almost since it was bought, although there was no sale.

The same has been true for eBay’s other purchase, of voice-over-IP service Skype. A recent report in the New York Times said its founders were also considering buying Skype back from eBay.

Under eBay, the site has floundered a little bit, but made some changes, such as unveiling a new Web-centric look and feel and a new partnering program last fall that represented a major shift for the online discovery service.

In that change, users no longer had to register for the service or download its toolbar to “stumble” the Web.

Terms of the deal were not released, but we’re digging! Um, stumbling!

More to come, but here’s the full press release from the company, as well as a video I did at the party StumbleUpon threw after getting acquired by eBay, including an interview with then-thrilled Camp:

StumbleUpon Goes Independent; Backed by Founders and New Investors

April 13, 2009 – StumbleUpon, the best way to discover new content on the Internet, today announced that after nearly 2 years as a subsidiary of eBay Inc., it has returned to the ranks of an investor-backed startup. StumbleUpon is now backed by the original company founders, Garrett Camp and Geoff Smith, as well as a number of well-known investors including Ram Shriram of Sherpalo Ventures, Accel Partners, and August Capital. Camp takes on the role of CEO of StumbleUpon.

“We are grateful to eBay for its guidance. However, we realized there were few long-term synergies between the two businesses. It is best for us to part ways and focus on our respective strengths,” said Camp. “This change makes it possible for StumbleUpon to continue to innovate and focus on becoming the Web’s largest recommendation service.”

“StumbleUpon helps users discover the best of the web–it’s a way to find interesting content you wouldn’t think to search for,” said Shriram. “StumbleUpon’s personalized recommendation engine brings serendipity back to websurfing, and lets users sift through socially-endorsed content with a single click.”

StumbleUpon will remain focused on helping people discover interesting content by increasing the accessibility of the StumbleUpon service and the quality of recommendations. In addition, StumbleUpon has plans for several new products and features to be released in the upcoming months.

OK, strike that last one, but the valet parking was nice.

Last night, it was hearty partying in Silicon Valley, with two big events that attracted the digerati in numbers. Tech folks, for all their earnest seriousness about changing the world, like nothing better than schmoozing (and, last night, bellyaching about the iPhone price cut).

That was all to be found at the luxe affair thrown by August Capital at their even more luxe offices in the heart of Sand Hill Road last evening after work. It has long been one of the industry’s favorite events.

This is your quintessential top-line Silicon Valley party–heavy on VCs talking deals, entrepreneurs sucking up to them and also reps from big acquiring companies like eBay and Google and a passel of press drinking mojitos and being alternately snarky and annoying. Not so trendy, as the later iLike bash, but classic tech festivities.

Ah, it’s a grand life here.

But see for yourself: