we're (serpIQ.com) building an affiliate system this month for our product. Hope to have it online by April 1st. Not sure what you mean by disappearing from the credible startup world, affiliate programs are a fantastic way to grow your user base, especially for bootstrapped companies.
The reason affiliate marketing sometimes backfires is that you can't filter out who's writing about your product and what they're writing. 37Signals stopped taking new affiliates, and instead started a 'Tell-a-friend' program coz these kinds of recommendations are more personal and have better chances of getting looked at favourably. If I could choose, I'd pick a referral program over an affiliate program. But thanks…
Also, some cannibalize your sales.. they rank for brand keywords or bid for brand keywords, and take away sales you otherwise would have gotten anyway.