What is 10chars?
10chars an abbreviation for "10 characters." It is used as a method of bypassing 10 character limits in forums when your post would have otherwise been too short.
It's now mostly a joke, however. Posters will be most likely seen just using the number and adding a humorously relevant/silly/sexual substitute for "chars", especially when their post is already above 10 characters.
Haha... Rick Roll'd muthafucka