So very obnoxious. I can understand blocking actual games (flash game sites, etc) but I've never understood why companies block forums for hobbies but don't block reddit, ESPN, etc.
Depending on the filter it is probably just categories. I manage two different blocking systems here at work. Both are primarily filtering on categories. Many years ago I was asked to implement this and I printed out the categories and let my boss and his boss select the ones to block. We do white list somethings. They wanted to make sure everyone could get to the more common email websites (aol.com, yahoo.com, gmail.com etc.). So they weren't completely draconian.
Even here on CAG there are images I really don't think are appropriate to display here at work. Half naked women avatars/signatures. I turned all that crap off years ago. I don't think it is as bad as it once was. But I certainly don't want those images on my screen for a co-worker to see.
We had one manager get caught looking at porn. He claimed he clicked on something and it just popped up (the porn). Where he worked there are only a couple of women (warehouse) but one of them happened to be who saw it and reported it. Dumb.
We block Youtube from almost everyone. As well as a Facebook. Many years ago when I was asked to put this in place we had crap for Internet/bandwidth. So it made sense.
Little by little some of the stuff we block makes less and less sense. We have a few different people who use Facebook for actual work stuff. At least two different women manage our companies Facebook page. Youtube is an even bigger issue now as more and more training and help videos are being uploaded. I use Youtube several times a month if not more for legit business reasons. Be it trying to learn how to do something or researching a product or service.
Hell WBMasons.com has embedded youtube on it.
We have plenty of good bandwidth now so we are always considering relaxing some of these things but need upper managements approval. Also now Verizon and AT&T wireless have good service (didn't until about a year ago) here so more and more people can stream stuff on their phones.
We also have Wifi that is unrestricted. Password isn't supposed to be given to just anyone but when I look at all the devices that are logged in it is obvious the password has made it around most if not all the office.
It isn't a problem until it is a problem. A couple weeks ago someone was casting Spotify to a TV in the Executive Conference room. Likely an accident. And luckily no one really noticed. Had that happened in the middle of a meeting? Wifi password would have been changed immediately and not given to anyone below management.
So here it is a mix of there was/is a business need to filter and to keep some people from goofing off on the Internet all day. There was a time were we ran crude reports on a few people who were goofing off so their managers would have proof. Luckily we haven't been asked to do that in years.