The fact that eBay (EBAY) is PayPal's largest merchant isn't exactly surprising. The auction market is huge, and it's also the online payment company's parent. Yet, the word out of the 2010 Media Summit in New York last week is that Zynga, the social media games company, is the second largest merchant for the payment environment. Social games are growing rapidly, bolstered in large part by the rise of Facebook, which now boasts around 400 million users.

As social media companies realize they need to move to the next level -- from adoption to revenue -- the virtual goods market has emerged as a substantial revenue stream, and Zynga's environment appears to have been designed to capitalize on it. According to an estimate by Citigroup (C) analyst Mark Mahaney, PayPal took care o$500 million in virtual goods payments last year.

Company attitudes toward social media sites vary. Some swing the doors wide open, allowing employees to tend to their Facebook farms and update Twitter statuses throughout the day. Others lock 'em down, keeping non-business site access to a minimum.

A recent study found that, in the United States, 77% of employees with Facebook accounts check in with the community from the office. And, the amount of time they're spending in this part of the online world is growing. In the United Kingdom, another study found that 57% log in regularly from work, costing their employers 40 minutes a day.

Philip Wicks, a consultant at Morse PLC, a technology research firm in London, "It isn't just something you can do for half an hour during a lunch break but all through the day and because of that, it has a huge impact because people aren't necessarily concentrating on what they should be doing during the day." He estimates that this translates to lost productivity of $2.25 billion a year.

It seems like the obvious move would be to block the sites, but William Beers of PricewaterhouseCoopers disagrees. "Instead of trying to shut it down, I think we should try to embrace these technologies, put in a nice policy that governs it and explain to users the risks related to it, provide some training and then see what business benefits we can have from it," he said.