I agree that XP should be a measure of site participation, but I still think we should get XP from voting rather than just from posting. The site is designed for people of all skill levels, not just for Perl gods who can answer all the questions that come up, and thus you have to think of people just starting out when you make these policies. A lof of people are just nervous to post (some monks are not as diplomatic as others when a post is bad).
The XP that come from voting encourage not only better post (because you come to know what you like/dislike about certain posts, but also what others in the community like/dislike), but they also encourage new monks to read all kinds of posts, not just the "easy sounding ones".
--Ivory