President Barack Obama kicked off his 2012 re-election campaign last week on — where else? — Twitter and Facebook signifying the continued importance of social media in the U.S. presidential elections. Obama has plenty of Facebook and Twitter followers ready to back his campaign a second time around. But where the Obama Facebook account works as a source of inspiration for digitally minded politicians, the Obama campaign this time round falls well short of the rousing “Yes we can!” spirit we’ve seen from his camp in the past.

What’s hot in social media investment this week? Social commerce, crowdsourced content hubs, apps specialists and, yes, social media monitoring. This week’s freshly funded startups brought in a combined $409.9 million, thanks mainly to SocialLiving’s massive $400 million haul.

In October, we noticed an interesting trend forming: social media, and in particular, Facebook, over the first half of 2010 was driving the UK’s resurgent online ad market. New numbers are in this morning and the story hasn’t changed: the social media ad spend grew at a staggering 200% rate last year to help the online display ad sector nearly crack the £1 billion mark.

Backtype operates one of the web’s favored “free” social measurement and analytics dashboards. Backtype boasts it has the best tool to deliver Twitter analytics – a notoriously fickle proposition – as it was able to build a profile of every active Twitter profile in under 24 hours with a “high tech stream processing system.”

Fast Company may have said it best, when it described Dailybooth as a micro-blog, like Twitter, “based on photos.” So far the user base appears to be dominated by tech-savvy teenagers with photo-capable smartphones. Could the iPad 2 crowd provide yet further growth?

How much is a single, glowing Facebook recommendation worth to a marketer? Just how valuable is a strong endorsement from a blogger in determining future sales? And just how engaged is the average TV viewer with a popular show with all these distracting networked gadgets, tablets and laptops in the room? Syncapse answers some of these questions in a new piece of research out this week.

For the 198,775 people who’ve declared their allegiance to the Microsoft Zune, these are troubling times. News reports are swirling that Microsoft will kill off the iPod-wannabe imminently. The only problem is Microsoft is denying the reports, but nobody’s listening. Yes, there’s a Zune metaphor in there somewhere.

The shakeout of winners and losers has begun. Google’s now infamous search algorithm change last month is diverting eyeballs away from so-called content farms and middle-man publishers. Who gains? Big media, for one. And brands-turned-publisher, too.

Talk about your #winners. Charlie Sheen joins Twitter on Tuesday and already this morning he’s closing in on 1.2 million followers, surely a record for Twitter clout. Right? Let’s take a look.

Last month we went in-depth looking at the trends, activities and passions driving the U.S. online market in 2010. Today, we look at Europe as comScore publishes its 2010 Europe Digital Year in Review. Like in the U.S., there were some big winners and losers.