Resteeming gives no direct rewards for anyone, but it may give an article more exposure.

Say that person A wrote an awesome article, but he has no followers, so almost nobody reads the article and almost nobody votes for it.

Then comes B, which has a lot of followers, he gives a vote to the article and resteems it, and as a result the post will get lots of upvotes.

Both A and B will win on this, A will get author rewards from all the upvotes given by the followers of B, and B will gain curation rewards.