Fortune’s latest cover story is about the new tech bubble, and whether the dreaded “b” word is really appropriate. One thing for certain, however, is that Silicon Valley’s tech community is not sharing in mainstream America’s labor doldrums.

Between March 2009 and March 2011, the U.S. economy lost nearly 1.29 million non-farm jobs. During that same period of time, however, a number of private, VC-backed tech start-ups went in the opposite direction. In fact, just three of them alone added more than 11,000 new positions during that two-year period, according to documents filed with the SEC:

  • LinkedIn LNKD : 1,288 total employees (79% hired since March 2009)
  • Groupon: 7,107 total employees (99.5% hired since March 2009)
  • Zynga: 2,200 total employees (92% hired since March 2009)

All three of those companies also indicated plans to hire even more new heads in 2011. And one would assume we’d see similar trend-lines from fellow Internet giants like Facebook, LivingSocial and Twitter — were they to file such things with the SEC (which they don’t need to until they plan to go public).

Things obviously are bad but, without Web 2.0, they could be even worse…