There have been dozens of cases of workers warned or fired because of something they wrote on a blog. In a survey by Proofpoint, over 57 percent of executives at 332 large companies said they were concerned about blogs as a source of trouble for their companies. Although the balance between free speech and an employer’s rights is still up for grabs, generally, if you’re an “at-will employee” you can be let go at-will as long as anti-discrimination laws aren’t violated.

It can be tricky to drag public comment out of a company without first routing through the sanitizing filter of a press office.

Even if senior managers trust staff not to give away the company's commercial secrets - and many don't - there are still enough worries about libel and (for publicly listed companies) stock market disclosure rules to have the legal department waking in sweats for months to come.

There are plenty of areas of business where people are judged on their knowledge, and the competitive edge - and thus the safety of everyone's jobs - is the thickness of a single good idea. Sharing it all on a weblog, with competitors or (worse) an office rival is not really wise.

There is a risk that an ill-judged comment could be seized upon by the media or disgruntled investors.

The best non-corporate blogs are spontaneous and genuine. Poorly written corporate blogs can look fake -- or perhaps worse, they reveal incompetence on he part of the writer.

Like practically everything else on the Web, blogs are easy to start and hard to maintain. Writing coherently is one of the most difficult and time-consuming tasks for a human being to undertake. So, far from blogs being a cheap strategy, they are a very expensive one, in that they eat up time. As a result, many blogs are not updated, thus damaging rather than enhancing the reputation of the organization.

Blogs make many organizations look like disorganizations, with multiple tones and opinions. Contrary to what some might think, the average customer prefers it if the organization they are about to purchase from is at least somewhat coherent.