Once heated, warring enemies, Internet juggernauts Facebook and Yahoo are putting down their gloves, joining forces and cross-licensing their patent portfolios. But that's not nearly the biggest news to come from this venture. The two companies will also begin an advertising sales and distribution partnership, which allows Yahoo to show Facebook Like buttons in its ads. The announcement brings a somewhat anti-climactic end to the long running patent feud between the two brands, effectively opening up the entire patent supply of each company to the other to use as they please. The advertising sales relationship is expected to help each company improve its ability to secure larger brand advertising buys and spread their placement across both properties.