I found this fascinating quote today:
While Plinky is certainly an interesting service, and one I might start playing with, it’s not something that will help you improve the quality of your blog. At least, not yet.Chris Charabaruk Online, Jan 2009
You should read the whole article.
I may play with it myself sometime in the future (hopefully once it stops choking on attempts to hook up my Blogger account ^_^).
EDIT 01-24-09: My reply to the original post.