We were thinking of canonical links and backlinks to the original article

Oops, it looks like the cite tag was changed a while back. You are correct about cross-domain canonical links. Hopefully this will avoid duplicate content penalties. If you can, including that in the benefits of your service and in the FAQ should help with signing up bloggers.

Ah yes the good old user registration problem. Hopefully it'll be fixed with the mining soft fork that's coming next where people can mine for their accounts.

Where can I find info on the mining soft fork?

Totally agree, steempress is only the first step here, in the future we want to reach a full integration where you can directly upvote/comment on the blog and it communicates with the blockchain (with all the underlying effects)

Steempress looks great! As to the upvote/commenting, I started looking at SMTs. I'm working on an app that I want to allow users to post pictures and have upvotes/comments integrated into the Steem environment to be able to earn for their engagement. Am I looking in the right place?