The year's biggest valuation is also the most debated: Is YouTube going to be a steal at Google's purchase price once it becomes the future of TV, or a growing source of legal hassle as more networks request to have their content removed?
2 Massive by Microsoft, $200 million-$400 million
The gaming industry's most active in-game advertiser was a wise investment for Microsoft, which was a minor player in the crowded market.
3 Atom Films by Viacom, $200 million
A move criticized by some as a me-too acquisition by Viacom, which shelled out $200 million for the seven-year-old web company. But Viacom did get a global digital media officer out of the deal-Atom CEO Mika Salmi.
4 DMarc by Google, $102 million
DMarc marked Google's entry into the radio-advertising business. The deal was valued at $102 million upfront but could be worth as much as $1.2 billion, depending on how dMarc performs over three years.
5 Xfire by Viacom, $102 million
Xfire's social-networking, instant-messaging and gaming-information services so impressed Viacom it was willing to shell out upward of $100 million.
6 Platform by Comcast, $80 million
The Platform is a cornerstone of Comcast's fledgling online-video play. The broadband-services provider cost the cable company in the neighborhood of a rumored $80 mil.
7 Grouper by Sony, $65 million
Sony gave copyright-shirking YouTubers a run for their money by purchasing this legit video-sharing site. Should its main competitor ever go down in a sea of lawsuit-induced flames, expect Grouper to emerge as the next major player.
8 JotSpot by Google, $50 million
Google's venture into the wiki world was a questionable move for a company that has been notoriously low on ad inventory. Offering JotSpot's previously paid services free to users also raised questions of monetizing possibilities.
9 Petfinder by Animal Planet, $35 million
The year's biggest (and cutest) no-brainer was the announcement that Animal Planet would unite TV fans and pet owners to help locate long-lost animal friends. Petfinder could give a dog a bone or five thanks to the $35 million buyout.
10 Wired.com by Conde Nast, $25 million
Better late than never. Nearly a decade after its initial purchase of the tech mag, Conde Nast finally put its hot print property under the same roof as its web counterpart.