I believe that co-op ad networks still work. But you risk a -950 penalty.
Today,i registered one of my sites at automaticbacklinks.com
I know google punishes auto link exchange sites.
But this one follows a new strategy
Automatic Backlinks - Frequently Asked Questions
This made me curious to do an experiment with this site.
If you have any previous experience with this site,please share it here...
Ouch! I would advise staying away from any automated link scheme. If google finds the network footprints it will start slapping all the sites in it. I am using IBL Builder if you want to try something that will not get your site slapped.
i think the codes that you put on the pages will leave footprints of an automatic link page creation or reciprocal linking page, which can earn you some negative factors with google-sometimes they do sometimes they just don't, it is a guess work there