You found a forum or a blog that you really like, or one where you think a product or service you have to offer would be wanted, or alternately, you contacted someone on a social network. You made a post that couldn't possibly have upset anyone, or maybe even all you did was click the "add" or "edit" button...
Banned? "Blocked at the request of the user?"
You have been Mistakenly Banned. This tends to happen in at least two main subtypes:
The "accidentally stepping on toes" form is that you did something that, unknown to yourself due to lack of experience made you look like trouble. In Type A, you're doing something the place or person considers wrong or a violation of netiquette, but you didn't know you were. Ways to invoke type A of this trope include...
- That post promoting your band or business or whatever looked like a Hit-and-Run Poster or a Spammer. (Most forums and other social media venues tend to look very suspiciously upon people who post a link or promotional topic and don't otherwise contribute, for example.)
- A political statement you made or a glowing review made you look like you were engaging in Astroturf.
- You brought up a topic that, unknown to your knowledge, was not a welcome one to discuss.
- Your Twitter or Facebook consisted solely of what appeared to be advertisements, you regularly post things the person you added doesn't want to see, or you appear to be or have been rumored to be a stalker or other threat.
- You made a Gannon Banned mistake or said something considered to be Fandom Heresy or Malicious Slander.
- You were really drunk or high or having an episode of mental illness or triggered and got into an argument or otherwise said/posted things that you wouldn't have done sober or well.
The "entirely innocent" form is that whatever happened was no fault of your own. Things that can lead and have led to this include:
- You picked a username that, for some reason, resembled that of a past Spammer or Troll or someone once involved in drama of some sort.
- Someone else in your dorm or house could have been a Wiki Vandal or a Troll.
- Someone made a mistake on entering the IP or used an entire range block. Or they mistakenly or intentionally blocked all IP addresses from a certain location or service, or prohibited people from signing up from certain e-mail providers.
- Someone hacked your account and/or otherwise posed as you for some reason. 
- The person you tried to add had been shunned by half your friendslist and assumes you're just adding him as a part of your friends' drama.
Either way, the best way to handle this is usually to step back, analyze your behavior to make sure your ban wasn't thoroughly deserved, and then try to speak calmly to someone in charge of the site, or to someone who knows the person, to ask what is wrong.
Keep in mind that actual spammers, trolls and other scoundrels often pretend innocence, and that making a Sock Puppet for ban evasion is, in many places on the Internet, itself a bannable offense.
This is a type of being Properly Paranoid on behalf of the board ownership or the person in most instances, as it's far easier to keep out some online users than to deal with them once they've made a mess. Related to Astroturf, Edit War, Fan Dumb, Fan Hater, Flame War, Gannon Banned, Garbage Post Kid, Hate Dumb, Internet Backdraft, Spammer, Troll, and Wiki Vandal for the actions that can lead to people actually uninvolved in them being Mistakenly Banned. The Gadfly is someone who is mistaken for Troll and may be subject to this.
No examples, please; it happens everywhere, and this is not a page made for whining about being banned.
- This is actually one of the most common claims of actual trolls or other internet riffraff trying to claim innocence - unless the hacking or the impersonator was so Out of Character that people immediately noticed it, you need to have an alibi almost more solid than one you'd have for court to get your account/privileges/reputation back.)
- At All The Tropes, the people in charge of the site are listed at All The Tropes:Contact us.