Your teenage nephew’s homemade videos may not win an award for creativity, or even clarity, but don’t dismiss the power of these amateur auteurs. A new ad effectiveness study shows that user-generated videos more than pull their weight when compared to the pros. They even drive sales.

Shaving is a necessary evil for most men, so they’ve little choice but to buy in to the multi-billion dollar industry. Until now, that is. Enter Dollar Shave Club, the company that’s done away with flash, aspirational advertising, and simply promises to provide high-quality razor blades every month – straight-to-your-door – for the low price of just $1 a month.

Unless you’ve been camped out in a deep, dark jungle (that doesn’t border Uganda) you now know the Internet this week has crowned a new viral video king, a “king” that features child-enslaving warlord Joseph Kony. It’s the most viral viral ever!, Mashable declares in a headline that’s sure to stay atop Google for months – or until somebody knocks off Kony. Who could that be? We have someone we’d like to nominate.

Two weeks ago, Google told us that the most-watched-ever advert to hit YouTube is Volkswagen’s “The Force,” a spot released six months ago during the Super Bowl. In another sign of its impressive social media savvy, Greenpeace is using the popularity of that advert against VW this week with a spoof of “The Force” that calls into question the German car-maker’s green credentials and commitment to a low-carbon future.

McAfee, the IT security company, along with viral video specialists Oddcast, launched an interactive Facebook campaign earlier this month to help inspire more responsible web surfing. The strategy was sound, and the online video was catchy, but was the Internet duly inspired?

What is the plural of Prius?, Toyota asks. It’s not meant to be rhetorical. In fact, the beleaguered carmaker is turning the question into a type of public vote being promoted these days throughout the social web.

Gillette, much admired for its viral video prowess and digital marketing chops, recently wrapped up in the UK what may go down as the dullest ever social media campaign: a contest to determine the public’s preference between the bearded male or his clean-shaven brethren.

Surely, they fade into the ether, never to be heard from or seen again. Not so for the Old Spice “I’m on a horse” spot. It may have fallen off Advertising Age’s “Viral Chart” late last month, but it’s getting new life from impersonators: Sesame Street’s Grover and the Blendtec guys.

What do the marketing departments at PepsiCo, Kia Motors and Pizza Hut (and not just them) have in common? They’re all plotting participatory, social media-inspired ad campaigns that star–get ready for it–you! Is this a sign of bold marketing-think or the latest indication that the creative guys have plum run out of ideas?

The Coca-Cola Happiness Machines are multiplying, even in a place where there’s little mirth today: London. That’s right, Coke has taken its viral YouTube video sensation to the other side of the pond, setting up its wondrous vending machine to a university campus in London with some predictably sweet results.