I made one post there, asking about the possibility of redeeming my games on Desura. Today I got a reply notification email, went to check the thread and am presented with: A simple 'no' would have sufficed.

Have others asked for the same thing?

Harsh if that's all you said to get banned.

Not cool, Frictional. It amazes me when companies do things like this; potentially alienate a customer while getting nothing in return.

Not as far as I'm aware. I don't remember anything in the rules/FAQ nor in stickied threads.

Of course I can't double check any of these now because they ~IP banned meeee~ (and I can't be bothered to go through a proxy). You'd think wouldn't you, but it did coincide rather neatly with me getting a topic reply notification... It's possible a community member reported it as spam and they auto-banned me I suppose. Still not cool though...

It's an automatic ban by their spam filter or spam reporting feature. Email them, tell them their automatic system made a mistake. Because it did.

How bizarre. Maybe it was an accident?

It is strange.

Do you have a link to the thread or can say in which sub-forum it was posted? It might be good to see if there are a reply there or not ("this thread is closed because of spam" or if the thread is deleted)

Here's the link from my reply notification email:
http://www.frictionalgames.com/forum/thread-18702-newpost.html

I tried to check it but because they IP banned me, even logging out and deleting cookies isn't enough to view the forum as a guest.

The specified thread does not exist.

I'd shout at them on Twitter. Always seem to help.

Set up another profile on your PC, you can try to login with that.

I'll still have the same external IP address since I'll be going through the same router, to the same cable modem, through the same cable which Virgin has assigned a static IP address. I'm fairly certain a new profile/login on Windows won't change any of that, sorry. Thanks for the suggestion though.
Maybe... I'll probably do that later. For now I have a band practice to be at and must be away!

Yes, thread is deleted... That is not automatic though, is it? It needs a moderator.

Not sure it's actually the case as I can't access the forum at all (two different IPs).

When I try https://www.frictionalgames.com/forum/, I get the message The exact same message when trying the specific thread.

Can anyone else give it a try?

Perhaps they're not to blame. I'm permabanned on WadjetEye for spam, scams, email harvesting and dictionary attacks. Use a proxy and contact them via the webform. Also, look yourself up on honeypot, just in case.