What is a sticky?
A thread appearing at the top of the forum listings that says "Sticky:".
If a thread doesn't receive any responses for a period of time, it eventually is pushed off the first forum boards. A sticky prevents that.
Think of it as sticking to the top of the page. It's up there so people notice them faster.
A sticky is a thread that is imformative and will help players. What the sticky means is that it will stay at the top of the front page because it is important. If there wasn't stickys, very few people would find those imformitive threads.