Mark Zuckerberg's college-spawned startup is supposed to hire its 1,000th employee sometime this year. I don't think that's going to happen. If Zuckerberg isn't talking about layoffs behind closed doors, one of his executives must be brave enough to bring it up. I don't think the company is going to issue pink slips. But I do think its headlong growth in employees will come crashing to a halt before the end of the year. Here's some back of the envelope math on Facebook's burn rate. Figure the company's operating expenses are divided roughly half in labor, half in operations like... [Tags: ad formats, adwords, back of the envelope, braintrust, breakout]