Down at the bottom of their blog homepage is a link:
See 15 more secrets - join the facebook page.
The "ethical bribe" of seeing 15 more postcards sends traffic to their Facebook page, where they can see said postcards in the Fresh Secrets photo album.
I think it's interesting to see how people market via Facebook - market as an active verb, moreso than just "having a Facebook presence". Personally, I'd like to see more examples of Facebook-exclusive content, such as events, or discussions, or chats. Second Life is home to many such branded events, even live music concerts and teleseminars; I would think the same could happen on Facebook (well, maybe not the concerts).
Are any of you seeing such events/offerings? How else do you think scrapbook marketers could be using Facebook? What ethical bribe could you offer via Facebook? An exclusive download link? Content available only via Friend communication blasts? What do you think?