My workplace has a filter which blocks all sites designated as “social networking,” which means no blog sites, no facebook, and of course no chat functions. Sometimes it even blocks news blogs, I know because I was reading the NY Times on my lunch break and it wouldn’t let me go to read a particular article because it was identified as a “blog.” You are allowed to check personal email through Google, AOL, Yahoo, etc.
I don’t think that any of that stuff should be allowed in a workplace environment. From the employer’s point of view, you are not being paid to read/write blogs or facebook, you are being paid to WORK. I only occasionally use the internet for personal use at work, and I’m annoyed by blogs or websites that identify themselves as NSFW. If you get fired for looking at something inappropriate on the internet, well that’s your own damn fault. You should be working, you lazy slug.