I also tend to lurk, albeit unintentionally. Often I'll only post when I feel like I have something to contribute that hasn't been said already by somebody much more articulate than I am. Since there are many intelligent, articulate folks on this site, I often just end up casually reading what's being said by others, occasionally contributing my two-cents-worth when I feel it might be helpful. Huzzah to lurkers!
Seriously, wouldn't you rather have me lurking if I had nothing more constructive to say than "Legolas is sooooooooooooooooo hot"?