For context, the following are anecdata from other S-1s that show profit (even if for just 1 quarter):

Google: http://www.sec.gov/Archives/edgar/data/1288776/0001193125040...

LinkedIn: http://www.sec.gov/Archives/edgar/data/1271024/0001193125110...

Salesforce: http://www.sec.gov/Archives/edgar/data/1108524/0001193125030...

While browsing IPOs from at least 2 years ago, eToys and Yelp had S-1s with negative incomes:

eToys: http://www.nasdaq.com/markets/ipos/filing.ashx?filingid=9223...

Yelp: http://www.sec.gov/Archives/edgar/data/1345016/0001193125113...

This isn't enough data to draw any conclusions, but it is interesting enough to ask the anonymous internet to finish the research since I'm tired tonight :)