Facebook has a history of snatching its competitors’ employees, but while Google paid an engineer $6 million so that she won’t defect to the social network, Microsoft has taken its efforts to an entirely different level – court. All Things D reports that after Facebook hired ex-Microsoft global ad sales head Carolyn Everson, Microsoft is considering a number of options including legal action. Everson, now VP of global sales for the social network may have to face a potentially grim scenario, but that doesn’t mean the same is true for Facebook.

“”Lawyer[s] at both companies have been in back-and-forth talks in recent days after the hiring of Microsoft’s global ad sales head Carolyn Everson by the Silicon Valley social networking powerhouse to be its VP of global sales.”

Microsoft will most likely not compromise its strong partnership with Facebook. On top of the fact it owns more than 1% of the company, Facebook integration is a vital element in Bing’s future growth. The only objective edge the search engine has over Google is its integration with Facebook and various subsequent social features – most prominently Liked Results.

In an article covering the Microsoft-Facebook clash, SF Gate noted that “a fight would hamper the companies’ mutual goal of putting the hurt on Google”, but even the oldest rivals can set their differences in court. Google and Microsoft are teaming up to sue somebody.

NoSoftwarePatents campaign founder Florian Mueller:

“”Google and Microsoft have joined forces to take down a Texas company’s geotagging patent that they claim has been used in lawsuits against more than 300 entities, many of which are customers of the two companies”

Customer loyalty is obviously a very pressing priority for the two arch rivals, but not pressing enough to make Microsoft let go of its trademark war against Apple. In Jan., Microsoft requested a court to block Apple’s ‘App Store’ trademark claiming it’s too generic, and now, PCMag reports Apple has claimed the same about ‘Windows.’  This may seriously affect Microsoft, which has gone a very long way to prove its case against Apple, but at least it still has a chance of getting its hands around Novell’s patents. Unfortunately, that chance significantly shrunk after the Department of Justice raised some concerns claiming that if Microsoft would participate in the $450 million deal, it may seriously hurt rivals such as Red Hat in future.