As the Sun reminds us today: celebs are hot for Twitter and Facebook. Lady Gaga, Justin Bieber and Stephen Fry have massive fan/follower bases that hang on their every Tweet and update, a potential bonanza for brands with Twitter-savvy celeb spokespeople. Ah, but not so fast. New rules in the UK designed to protect the public from the celebrity-endorsed Tweet could impact this practice before it gets a chance to take off.

Google has unveiled overnight a series of upgrades to its now two-year-old project to make its search results more personal social. Starting today, you’ll see item like your colleague’s Tweets and your friend’s Facebook “like” recommendations interspersed in the search results.

Last week, we got a 2010 report card on the Web-based side of the digital economy. Today comScore releases its mobile year-in-review, and it is a completely different story this time around with Asia clobbering us here in the West with an overwhelming majority using their handsets every day to take part in the social web, download content and make purchases via mobile wallets.

Well, it’s Facebook official. Mattel, the iconic toy company, has reunited its most famous couple in a monthlong social media campaign just in time for Valentine’s Day. Was the boost in romance enough to goose Facebook fans, too? Here are the results.

After reading in today’s Wall Street Journal that private investors are valuing gaming developer Zynga at between $8 billion and $10 billion, and then this beaut in the New York Times – that JP Morgan is looking to raise up to $750 million for a social media investment fund – I figured it’s now time to get out a scrap of paper and compare the present, pre-IPO multiples as we know them for the next batch of Nasdaq darlings. The numbers remind me of another heady period a dozen years ago.

Facebook unveiled yesterday a much-needed revamp of Pages that give admins the flexibility, and, more importantly, visibility to interact with the social web in the name of the fanpage they represent. Here’s what it should mean for all you admins flying the flag for multiple fanpages.

2010 was a good year for e-commerce and online advertising, and a great year for Facebook and Twitter. It was another rough year for Yahoo, AOL and email. ComScore delivers its 2010 U.S. Digital Year in Review report, packed with interesting data points that we’ll quickly summarize here.

Audi, the German luxury car brand, has directly merged old-school advertising with new media, making it the first company to feature a promoted Twitter hashtag in a Super Bowl commercial. While the pundits and public are still divided on the number one Super Bowl spot, we’ve sized up here the newest promoted tweet strategy. Beware. The results may surprise you.

What did the online public think of Groupon’s $3 million Super Bowl spot? A wacky laugher or potentially reputation-damaging gamble? Maybe this poll of polls will clarify.

The NFL continues its blitz on building up its non-American fan base in a geeky way, this time teaming with Foursquare to create a virtual Super Bowl party for the big game on Sunday early Monday morning.