Filtering blogs

Wired News reports on companies that are using filtering software to prevent access to blog sites: No Longer Safe for Work: Blogs:

Robert Mason (not his real name) would love to spend a few minutes during lunch catching up on blog posts from around the web, but his company doesn't allow it. The financial institution where Mason works as a vice president has security filters set up to block access to -- among other things -- any website that contains the phrase 'blog' in the URL.

It can be dangerous to let employees access to a type of technology that can connect those employees with frequently-updated sources of information about work-related topics, right?