Here's a technique that has worked for me - posted in the main forum. It uses Twitter and then boosting the post using AMF.

Hi everyone l am finding better results now with a system of pay per click solo advertisments as members of these type of websites tend to click the link as they are getting paid, the free type of solo advertising tend not to get good results you can send many 1000,s of ads and not get any clicks, as with paid solo ads the click thru can be as high as 50%, here is a site that has a cash system A Total Cash Site it show how it works.
I still use credit based sites also but little results...