Slugs

Lately there seems to be more slugs in my garden. I usually ignore them as they are relatively harmless and their number is insignificantly small to be a major nuisance. Their cousin, the snails are more notorious and they have caused some damages to my plants, but the most destructive pest found in my garden would be the grasshoppers. Yesterday, I almost squashed some slimy slugs. What were they doing at my doorsteps? Were they having a peaceful protest or something like that?
For those of you who doesn't know what a slug is, here is a picture.

For me, a slug is just a "homeless" snail. Wanna keep one as a pet? They are relatively easy and cheap to keep as pets. No? They are slimy and icky? You prefer a cute fluffy toy dog? Well, to each his own.. Anyway, here are some links on slugs:
 http://en.wikipedia.org/wiki/Slug
 http://www.velvetdragon.com/cyberslugs/realslugs.html