+add this: worth it?

Has anyone tried this, and/or what do you think about it?

Tried what bud?

Regards,

Lee

I've been reading a little about this. From their own words at addthis.com:
"AddThis is the #1 bookmarking and sharing service, served over 20 billion times per month."

Sounds good but I'm wondering if it is as good as it sounds!