You can not control one way back links. Therefore Google values it a lot. Now algorithm is such that if you are linked from unworthy sites, you are not penalized. If that was the case then, any body can bring down a high profit neighbors website, simply by creating 100 links of that site from a porn site. Problem is if you are also linking to those sites. If you are not, be worry free!
really nice feedback...i've used this service few days ago...its better creating a clean backlink with high quality site...