I think if you do a redirect there is no advantage to that. Travel to http://www.easterbingocards.com, there is content there for the search engine to index and return as a result (content that also of course has a lot of the keywords that are being targetted).

(Unless you're talking about doing a reverse proxy to the content of the tarsnap site, but I believe there is also not much advantage to that since the search engines pick up on duplicate content)

[EDIT: this is coming from things I've read not controlled experimentation. I don't think you can be an 'expert' without the latter so maybe I should not have responded]