ISP blocked due to abuse?

Well, it seems today that I'm now unable to post anything over at the 4chan imageboards, otherwise I get this message:
"Posting from your ISP has been blocked due to abuse. [More Info]"
I can still browse the site, all the images and threads load fine, I just can't post. What gives? I've never posted spam or porn.

Quick go to an internet caffe or an unsecured wireless hotspot where you can post on 4chan.
Post your question at the new questions board : http://boards.4chan.org/q/
Make the thread about ISP bans in general. Someone posted one about Venezuela but didn't get much attention. Don't be selfish! Help us out!