SThe revolving door at Facebook has been swinging less of late. Two top designers, Katie Geminder and Eston Bond, left in August and September. But the economic crisis seems to have scared the rest of the social network's staff into their seats, wondering when the ax will fall. There have been no layoffs, but we keep hearing tips from inside there's a hiring freeze on. In fact, there's not: Facebook's unofficial second-in-command, COO Sheryl Sandberg, asked CEO Mark Zuckerberg to institute a freeze, and got turned down cold.And yet Facebook will end the year with 750 to 800 employees, Zuckerberg has said — a far cry from the 1,000 employees he projected at the beginning of the year, when Facebook had only 450 employees. Call it what you like, but those are 200 jobs that have gone missing. One would think that Facebook, more than ever, would have the pick of the litter. But its potential employees can do math. Facebook's hiring managers do not have the hot hand they played earlier this year. The turmoil within Facebook has made an impression on potential hires. As have Facebook's financials. Facebook raised $240 million from Microsoft in a deal that valued the entire company at $15 billion. And the company is making real revenues, though they're small by comparison to MySpace; the most solid projection for 2008 is $265 million, down considerably from the $300 million to $350 million Zuckerberg once thought it could make this year. All the while, it is spending heavily on servers; Facebook's pages, which must chart a user's social connections to determine what news from friends to display, are more computationally intensive than, say, a trivially simple Web search engine like Google. That means, in essence, more money spent on servers per user. What that means: Facebook will have to make more money on advertising per user just to stay even with Google's cost structure, let alone exceed it. It's far from that point. Most importantly, it's hard for outsiders to see the upside in Facebook shares. Most assume Facebook will issue them options, and wonder how those will appreciate enough to make them rich. In fact, Facebook has been switching to grants of restricted stock — a maneuver Google and Microsoft, too, has used when a lofty share price made options less attractive. Add skittish candidates and skittish managers, and you get a very tough hiring process; Facebook executives might actually like to hire more people, especially in engineering, but they're having a hard time finding people who meet their requirements and are willing to take the job. Zuckerberg doesn't have to institute a hiring freeze; his lofty opinion of his own company is putting enough of a chill in recruiting to keep costs down.