In an increasingly crowded lead gen. marketplace it's more difficult than ever to make your advertising stand out in the multi-offer environment.
One emerging technique that seems to capture the zeitgeist is the 'double opt-in' or DOI. Market researchers (often at the cutting edge of online lead gen.) moved to this process years ago to build their online panels, now the rest of the market is catching on. I'm currently seeing lots of demand from e-tailers and travel companies, to name a couple of sectors.
But be careful before you suddenly demand all of your OLG on a DOI. Most quality publishers will not operate on a DOI and so arbitrage is the answer (managing the risk from single to double opt-in). You'll even have to negotiate hard with the affiliates to pay on a DOI as they are often suspicious about email deliverability.
So if you willing to take up the double opt-in challenge, it could provide the answer to quality you're looking for...