Efficient and umbral use the feedbacks on your site has very important for Google. For this you may use this interesting resource.
The advantage to this technologies founded in that that you manage themes of the feedback themselves. This much useful and is directed on thematic sites, which uses Google.
Also here there is possibility to sell text. There is two modes: direct and assotiative. The First enables most sell the links and fix a price. The Second has already installed price. This will spare your time, but price enough low 
One defect of this place in that that not all sites will be able to take part in this project. Here, there is minimum restriction - 3 Page Rank.
Judge themselves and arouse themselves.