Do social networking sites boost office productivity or kill it?

Is that employee preparing the financial report the boss requested or checking out YouTube to see that amazing triple play that was all over sports radio this morning?

Did that tweet just sent out over Twitter close the deal with a key client, or was the sender just chatting up her recipe for blueberry pancakes?

Millions of such questions are being asked in the ever-expanding world of social networking, which has been a boon to countless businesses but also ranks as a tempting personal communication tool that can cut down on productivity in the workplace.

Experts say the wildfire growth of Facebook, Twitter, YouTube, LinkedIn and other social media has caught some companies off-guard. Instant communication is great, but how can businesses control personal tweeting, Web surfing and friend-collecting on company time?

"It's like any other business decision. You have to lay out the ground rules," said Jessica Hawthorne, employment-law counsel for the Sacramento-based California Chamber of Commerce. "Companies have to establish what can and cannot be done in the workplace. These things do need to be thought out, because it's happening so fast."