This is how it works, as excerpted from Monica's blog:
"I have agreed to send something nice to the first 3 bloggers who post a comment on this blog entry. In turn, those 'first three commenters' who respond to my post will honor the pay it forward concept to the first 3 people who post on their blog… and so on. So if you're interested in participating in this, be one of the first three to leave a comment. Please remember that if you agree to pay it forward, you need to post this acknowledgment on your blog, link to me, and pay it forward to three more people."
I don't know what the something nice will be yet but probably some quirky items I have lying around.