Mitch Joel has put up a post called Is Your Personal Brand Hurting Your Career?. He says:
Most companies look towards either the main corporate brand or the CEO/President as the focal point for all attention, so when someone starts to rise through the popularity of a Blog, it is often not only frowned upon by senior management, but also talked about in the corridors by co-workers.
This is very true. I speak not from experience — not enough traffic to my blog or a high enough profile to make our senior executives jealous! However, it’s not hard to see a day when someone from the company makes it big in the blogosphere, Twitter, or elsewhere. That might be one thing if they get famous for doing a funny dance on YouTube but quite another if it’s for expressing businesslike opinions, albeit ones of a personal nature.
Anyone big online probably has enough information out there for them to be traced back to their company so when a Westpac employee starts opining about the economy in competition with their authorised economic spokespeople, it’s going to be interesting to see what happens.
Maybe I’m getting old but it’s tiring to hear about Gen Y when you’re not a member of this golden tribe but you still feel hip not hip-replacement in this space. If there is truth in the distinctions, however, your Gen Y is not going to understand why they’re being shot shut down for offering thought leadership in the platforms they’ve grown up with. And soon they’ll make up a sizeable proportion of companies and their frustration will have a major effect.
Does your company have a policy in place to deal with this? Given how Australian corporations are lagging in this space, I doubt there’s been enough thought around this in many companies.
Inside the Box 
I find the executives very supportive and encouraging of my blogging activity, both here and in EMEA/US.
The IBM social computing guidelines have been helpful too (disclaimer – I work for them!)
You see from time to time staff (I work for Telstra) on forums offering tech help or correcting inaccurate statements. I think that’s great to see.
I think guidelines are important to assist well intentioned employees that may cross the line by unknowingly disclosing non-public information that could get them in trouble with their manager.
To keep things simple, the golden rule should be for all employees with a SNS, blog or is not to post content that you or your manager wouldn’t want to see on the front page of tomorrow’s newspaper.
Cheers,
Mike