A freakish person who doesn't just creep around corners and stalk people; they lurk about, following and annoying those who think that they are a weirdo (which is everyone). They are always THERE; in the background of a picture, standing right behind you while your waiting to get picked up from school, hiding in your shower...you never know they're there.
Gosh did you see that guy's dad following us last night? He was hiding in my shower when I got home! He is such a LURKER.
One who commits the act of lurking: Looking at people's comments/blogs/bulletins/friends/ect. but ever talks to said person. These people often have no life and are on myspace as much as possible. Some are quite ugly and have absolutely no social life.
A lurker is the female version of a creeper. Lurkers are girls that are weird, odd, or anti-social. They almost never like attention on themselves, and are usually creepily quiet. They can sometimes be stalkers.