I've not been banned from any forum, social media, online gaming or any other service providers. I have been suspended on OcUK on 3 occasions though.
1. In 2010 I think, I had too many OcUK forum tabs open and was meant to respond to a thread about the national lottery. However, I unwittingly replied in the Random Image thread. I later realised that all posts in the Random Image thread must include a picture otherwise it's a 2-day ban
2. Can't remember which year, might have been 2013 or 2014. A thread got deleted and everyone who posted in that thread got banned for 2 days. Not sure which thread it was, probably something political or sensitive.
3. In 2017, I posted an Irish joke and that was a 2-day holiday, citing that Irish jokes are racist.
The strictest forum by far though was a Disney-related one. There were 2 of us (me and a friend) and we lasted about a month before we sacked it off. We wanted to connect with other adult fans and avoid kids. However, we weren't allowed to say how old we were, so it was impossible to tell how old the other posters were, and there were strict rules about user names. Any media that got posted had to be on-site, so couldn't link or embed to YouTube, deviantART, Flickr etc otherwise it was classed as 'advertising'. We broke so many rules that it was like stepping on eggshells.
I also got suspended from AOL for 2 weeks
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Things like AIM were off-limits but I could still access webmail and there was an automated email in there saying that I was suspended but no explanation. I never heard back when I queried it. Thankfully though, it was 2009 and AOL hasn't been my internet provider since 2001.