So Microsoft has offered to buy Yahoo for $44.6 billion. If accepted, it would certainly shake up the tech world. But what would it mean for online video? It’s on Steve Ballmer’s mind. In his letter to Yahoo he mentioned video specifically:

Emerging user experiences: Our combined ability to focus engineering resources that drive innovation in emerging scenarios such as video, mobile services, online commerce, social media, and social platforms is greatly enhanced.

Each company has something the other has lacked. Yahoo has a vast audience, but not much ambition or focus (peanut butter!). MSN doesn’t have the audience, but Microsoft has always been cut-throat when it wants something. While we’re still digesting and analyzing the news, here’s a quick rundown of some immediate implications should the deal go through:

Traffic Stats: According to the most recent comScore stats, Micro-hoo would generate 509 million video plays, giving it 5.4 percent of the market and placing it second behind Google.

Maven: Yahoo just bought is set to buy Maven Networks, which means Microsoft would power online video for Gannett, Hearst, Fox News, Sony BMG, the Financial Times, Univision, TV Guide, and others.

IPTV: Yahoo has a relationship with AT&T for services on their video boxes while Microsoft has a whole IPTV package. Yahoo services on top of a Microsoft IPTV layer could make Microsoft’s IPTV move valuable and worthy for phone companies wanting to offer video services.

Channel Overlap: Both companies offer video channels featuring UGC and professional content. Yahoo will most likely have to step up to MSN’s SoapBox.

Silverlight: Microsoft’s cross-platform video technology isn’t the Flash killer it set out to be; this would give the company the chance to integrate it across a large property and force adoption.

JumpCut: Microsoft gets access to Yahoo’s online video editing tool. While Yahoo hasn’t done much with it (Campaign mashup? Yawn.), the Redmond giant will find a use for it.

Facebook: Yahoo’s audience + Microsoft’s stake Facebook + JumpCut = some kind of killer video widget.

Xbox Live Marketplace: Micro-hoo will have both streaming (to a larger audience) and paid download videos, setting itself up in a better position to take on Apple’s download-only proposition.

Zune: Now Microsoft has access to millions of more people who won’t buy its handheld media player.

Need more Micro-hoo? Check out other GigaOm Network coverage:

• Dear Yahoo, I Pwn You. XO Microsoft.
• Google Drives Microsoft’s Hostile Bid for Yahoo
• Microsoft Offers to Buy Ailing Yahoo for $44.6 Billion
• WWD Debate: Microsoft Wants Yahoo, What do Web Workers Get?