A confirmation of Facebook's power has come courtesy of the online auction company that itself earned $2.2 billion in revenue last quarter.  eBay thinks Facebook's "Like" buttons represent a good way to increase sales.

Maybe you've noticed a "Like" button attached to one of eBay's Daily Deals, or its Fashion Vault.  Those didn't appear by mistake, and it's possible they'll spread.

Julie Haddon, Senior Director of Social Media and Integrated Marketing at eBay, explained in a statement, "Facebook plug-ins are some of the best marketing tools going right now.  We can't ignore the opportunity to reach 500 million people."

Haddon later continued, "We have a vibrant and powerful community of customers around the world we can engage with thanks to new social tools, platforms and channels.  It's a great time to be part of this social commerce revolution and we're excited about the future."

Granted, the "Like" button seems a little bit at odds with the nature of an auction; the average bidder shouldn't want to call everyone else's attention to a good deal.  Still, the button could serve to create a sort of wish list, or come into play when duplicate items are for sale or a charity auction's taking place.

At any rate, the tie-in represents good news for Facebook and also shows that eBay is willing to try new things.