A friend of mine has been seeing good results with Linkvana, so I decided to give them a try.
The summary is this: For $147/mo you get the ability to spam their blog network.
To start using the system, you define "Projects". One limitation is that each project can support only one domain.
You can then choose to have LinkVana create articles for you or you can paste in your own content.
Outsourcing content creation to Linkvana costs "credits". This seems like a waste of money, as it appears that you can throw any sort of old content you have laying around into the network.
If you create the content yourself, you have two options: Posts and Articles. Posts are 100-150 words and articles are 250-400 words. You can put one link in a post, but you can put up to three links in an article. I have about a zillion spin-source articles laying around, so I ignored posts and focused on articles.
I spin and paste an article, edit in the links, and submit it to Linkvana. They approve the article and it magically appears on one blog in their network.
Linkvana also has a new social bookmarking service, but that also isn't included in the monthly fee. 100 bookmarks costs 20 credits ($40).
It's too soon for me to tell if these links will have an effect one way or the other. It does seem like a good use of a data entry person. I will have one of my data entry people spin and paste articles into this interface as fast as it will take them and we'll see what happens.