I think that if there is a legitimate business/sales/prospecting purpose for your employees to access these sites, then they should be available. Our company allows LinkedIn and Twitter--but not Facebook. Facebook can be leveraged for business, but it is loaded with time wasting opportunities. But then again, so is the web overall.

Sales and marketing folks--let them have at it. Anyone else--nah...

I agree with Keith, is there a business need for access to these sites? Typically a company needs to first understand both its marketing and employment branding and sourcing strategies. These are typically the two areas that have the greatest need to be on social media sites. Once that is understood, these should be reflected in a social media policy that very clearly outlines the company's SM strategy, philosophy and ownership of key roles. This policy should also address what will not be tolerated.

Once you have this defined, then it's very easy to decide what the company should "allow" or "not allow."

If your employees want to be on these tools, give them access before official hours and during lunch. That way, the needs of both worlds are met.

I would say "it depends." Is there some legitimate business purpose that these tools would serve? There is a tendency whenever any new technology comes out (dating back, I'm convinced, to the telephone) for employers to be concerned about whether its use will enhance or hinder employee productivity. The key, in my opinion, is focusing on business need and business use.

It's not Facebook that's the problem. It's the potentially inappropriate use of Facebook - or the telephone, by the way - that is the problem.

Still, some employees need access to a telephone. Some, perhaps (even in the 21st century), may not. It all depends on the job.

An employee working in a communication department, responsible for interacting with the media, should have access to all of these tools.

An employee working in customer service, responsible for gathering and monitoring feedback from customers, should probably have access to these tools.

An employee working in accounts payable, quite possibly doesn't need access to these tools.

Employees have many opportunities to "waste time" in the workplace and those that are time-wasters will do so. But they'll do so with or without Facebook.

Many employers refuse internet use not related to work, or prevent access.Others police use, read employees' email. While these actions feel punitive and suggest a lack of trust, like someone's watching the assembly line, they are not uncommon. Ideally, you want to build a bond with employees, a sense of shared mission, that would boost productivity and employee retention, and self-monitoring so that all non-work activity is limited to breaks. So if you allow access, but at the same time build more rewards for productivity into your operation, and create minimum levels of acceptable productivity, you can monitor changes but also create a sense of shared success and your whole team "rowing in the same direction" that will be more beneficial to your organization than either ignoring the request or setting strict rules.

That said, the rising use of social media as marketing channels has led to job ads for social media marketers: for them, all of these media are effective tools. As a university career services officer, I have found or been contacted by almost as many "missing" alumni via Facebook as via LinkedIn. Yes, Facebook can be a swamp of temptations to play not work, but there are plenty of other opportunities for distraction on the Internet. Like other writers I believe "it's not what you have, it's what you do with it." A bigger time waster to me is people asking me to join more obscure sites, which I've decided not to do as a matter of policy. If and when Plaxo, for example, gains a critical mass audience, I might expand the number of social media I currently limit myself to. The danger of denying access to social media is fostering an employee roster of rusting Luddites, out of touch with how information is shared and product excitement is built.