you created a fresh blog hosted on WordPress.com for your property for this? This isn't how I would do it with that property; I will try to write more when I get home but spamming up a brand new WP blog isn't going to have the same affect (although with a regular linking campaign it will have a headstart over a fresh domain and be free), at least I'm doubtful it will, as spamming up a lot of other possible properties. I wouldn't use it as other properties that are more interactive, tied in with other users and less brand new content created in one spot at the same time.
For example a submission to a social bookmarking site (digg used to be my favorite since they changed I don't have a new one), a Facebook wall post set to public, an authority forum post (BHW gets love but don't spam us!), parasites like these are treated differently than creating a whole blog and Google treats them getting blasted with links differently too; those will rank for an exact match on your post title easy, your blog will probably not see the positive and quick results yore expecting.
The properties I gave as examples, even without backlinks they are going to be page 1s for an exact match possibly even in hours; your Wordpress blog has some extra authority behind it but Google still treats it as a new site - it isn't anywhere in SERPS when you throw some posts up all on its own.
Check rankings on content on your parasites before using this method but the biggest sign if it's a good property to just spam away is if it's a a social type site with user interaction as chances are these rank well on their own (and are just new posts not new sites).