The Most Innovative Viral Videos of 2009

What makes a viral video catching? Perhaps, like porn, being forward-worthy is difficult to define but immediately recognizable. On this principle, Mashable has rounded up the 10 most innovative viral videos of 2009 for inspiration as to what works. (And if you happened to notice it's Friday, than we're not denying these fun videos might be help you make it to the weekend.)

So what do men riding bikes on fences, musical stairs, disappearing camera phones and a man who can catch laptops with his butt have in common? According to Mashable, the marketers' "solid understanding of what a brand is, who is the brand's audience, and what moves them."

Also included in the list is an abominable attempt by Microsoft which illustrates everything NOT to do and a catchy ditty about a broken guitar which became a PR nightmare for United Airlines which demonstrates viral video is a powerful tool for consumers as well. Both entertaining and edifying, the list is well worth a look in full. One video that made the cut is below to get you started.