In the world of HTML (the code that is used to create web pages), is code for a non-breaking space (which is exactly what it sounds like a space that is not allowed to be broken, i.e., the word right after it can't be wrapped to the next line). vBulletin (the forum software used to run this forum) used to support such codesHTML entitiesbut doesn't anymore. For example, in many of my older posts, you'll see –, which means "en-dash"
Nowadays I just directly type en-dashes into my posts (they look like this--> ).