Hiho,

I asked myself if there is a Key included in the UT 2004 offer so i can play online.

You can get a key by contacting support after purchasing the game, so yes, you can play online.

I'm not sure if there is one or not. I have a hard copy somewhere around here but I don't remember using a key to use it. I don't know that the online community still exists anyway though, so it might be a mute issue.

I don't remember using a key either. There are some active servers but not a lot, wish it was a little bigger.

The GOG version has a preset key. I just tried and could connect to a server with it without any problems. If you need a personal cd-key for reasons, you should contact support and request one.

The attached screenshot was taken just now, so there are servers available apparently.