We hear about it in the news every so often out here in Silicon Valley: a big player at Google has left for Facebook. Or a Yahoo executive has been seduced by Microsoft. Or some perky young startup has snatched a head developer from a venerable software giant.

Silicon Valley's human resources arena, ripe with star engineers and executives, is like a day time soap opera, full of unexpected surprises and shocking betrayals. Every time a transfer of talent occurs, juicy questions immediately begin to pop up surrounding the jump. Were they abused at the first company? Were they offered a huge salary? Who got screwed?

I'd like to take an overview of several high profile transfers of talent that have occurred in Silicon Valley over the past decade. Each one is a soap opera in its own right and has in some way affected the fertility of the Valley's technological breeding grounds. If I leave any big ones out, be sure to contribute your own top Silicon Valley talent transfers.

Tim Armstrong, Google to AOL: This shocking transfer occurred in March, 2009, when AOL abruptly fired two head executives and hired Google's sales boss, Tim Armstrong. Armstrong had joined Google back in 2000, when the company's ad sales were minimal and it was still in stiff competition with competitors like Yahoo and MSN. Flash forward eight years and Google is bringing in nearly $21 billion in Ad revenue per year and dominates a majority percentage of the internet search market.

The acquisition of Armstrong signifies a change in branding and corporate goals for AOL, as it continues to move away from its past as a ISP towards a future in digital media and advertising.

Sheryl Sandberg, Google to Facebook: Sheryl Sandberg served as Google's VP of Global Online Sales before being snatched away by a hungry startup called Facebook in March of 2008. Sandberg's departure marked the end of Google's 'super growth spurt', which was capped with a $747 share price a few months prior.

It was rumored that Facebook's young CEO Mark Zuckerburg first met Sandberg at a Christmas party, and was impressed. Soon after she left to become Facebook's COO, which at the time was still a refreshingly new start up (and had a $15 billion dollar valuation).

Josh Elman, Facebook to Twitter: Although Facebook's former platform manager isn't as a huge name, his new home at Twitter speaks volumes to the current 'Twitter-mania' that Silicon Valley is going through. Facebook and Twitter are currently in a war (with Twitter having the upper hand) for the 'real-time' web. Elman's savvy on how people connect and communicate in real time is surely a gain for Twitter's growing empire.

Vic Gundotra, Microsoft to Google: Microsoft's 15 year platform evangelist, Vic Gundotra, broke the breach and went to Google in June, 2006. This was at the height of Microsoft's Silicon Valley envy, particularly the Redmond giant's jealousy of Google's growing search engine dominance. Ever since, Microsoft has been hot on Google's tail - most recently launching it's 'Bing' search engine, which surprisingly has the beginnings to usurp Google's hot streak.

So what does the future hold for Silicon Valley? While some big players in talent acquisition have emerged, there is always a hotbed of hungry start ups that have proved time and again that they compete with the big boys.

Although many of these start ups don't yet have the hiring resources and clout of the Googles and Facebooks, they are fast moving, ambitious, and have products that are set to change the world. Armed with the right tools, such as cost effective Applicant Tracking software, many of these small companies may soon make an apperance on the soap opera that is, Silicon Valley Hiring.