It's not for SEO. it's needed to get lots of references in search engines if anyone decide to input our site into google or yahoo. so quality doesn't mean much. The only request - it shouldn't be spam of guestlists or forums. Everything should look very natural. Like we spent several days posting about our site in different places. Please PM your offers.
The best way to get all your products listed is by a search engine sitemap (xml version) - I imagine some of your category phrases are competitive, but I would also guess that you have some long tail products that wouldn't need much more than some good optimization to get them first page rankings in the big three.