Used to bypass the automatic censoring devices that some forums, image boards, and online games use. These devices usually automatically convert any swear or derogatory word in a post into asterisks or dashes.
It can be a little bit annoying since you often have no idea what the poster was trying to say because all you see are asterisks that sometimes dont even match the number of letters in the word. It also makes reading some posts a hassle.
Methods of censor bypassing include replacing letters with numbers, removing a letter, replacing one letter with an asterisk so people have an idea of what you were going to say, and using slangs such as "effing".
Censor bypassing the word "fuck