I've been using Solo Ad Advertising for about half a year now... It was the most responsive advertising I EVER used in terms of RESULTS and, by this, I mean signups and SALES not just clicks on my solos... I used Solo Ad Advertising to promote other ad exchanges and, once, for example, I had a referral upgrade ratio of more than 12%, much better than the general upgrade ratio of that ad exchange... Using Solo Ad Advertising to promote other Ad Exchanges helped me A LOT to earn hundreds of dollars from my referral upgrades and purchases and also from scoring on the top 3 of some referral contests.
That isn’t to say that sales-y promotions couldn’t ever create results—as marketing “gurus” have proved. The results just aren’t as good as they could be. Take the biggest gurus’ results—the ones they boast about—and calculate their conversion rates. Often their marketing is comparatively ineffective. They just have massive volume, so the sales numbers are impressive.