Ad swaps. Exchange plugs for your ezine with another website, to run in each other's ezines. Offer to post their article on your article page in exchange for adding your article to theirs. Be sure to mention those freebies! Doing this on a regular basis with a rotating selection of web partners will keep your subscription page busy.
Allow any newsletter that wants to reprint your articles do so, but don't forget to include to tell them to include [your bio] at the bottom of the article