Here is a chart from James Pethokoukis at the American Enterprise blog, comparing the change in employment in recessions since World War II. The recession that began in 2008 should be obvious:
What's different? Probably a number of things. One is that companies have been shifting manufacturing jobs overseas because of high labor costs in America. Two is that the American economy, so long touted as a "knowledge-based" economy, has become more and more a paper-pushing economy, where jobs that go away oftentimes don't go back, because they weren't that necessary to begin with.
But I think the obvious answer is that Obama's high-tax, high-spend, heavy-on-the-regulations, hard-left, crony capitalist, statist administration has scared the beejeesus out of American businesses. That's why the unemployment curve flattened out and hasn't gotten back to pre-recession levels. Businessmen are waiting him out. 2012 can't come soon enough.