Are these healthy? I am noticing a lot of these in my comments waiting to be moderated in Akismet. I notice some of you bloggers let them float around in your comments and others don't.

Since I am fairly new to the blogging world I wasn't really sure what these were doing. So I followed the link in one and realized it was more or less other blogs regurgitating my posts for thier content. Some of the pingpacks relink back to my blog which can't hurt in search engine ranking. But what's the real motivation? What's you guys thoughts? I mean I am glad to share the news but is it crippling me in anyway that I am not seeing?