I would be pretty interested to know. I guess it comes down to your target market and what appeals to them. You could give away software or an ipod but having said that it depends how you go about doing it and how you market the idea across to current/potentiail/previous customers.
I think it can be really useful if you use things that typically arent useful or have such a good ROI...
Example: A couple years ago I had a webhost aimed at bands and musicians. I made a bunch of flyers, which usually are pretty worthless at least for me, and offered contests for guitars, music store gift cards, things like that, and it worked. People wanted to find out more about who would give a $500 guitar, and once they got in the door, BAM, nailed 'em.
We've had really good luck with a promotion that we've been running at various hosting forums (WHT, HostHideout, etc.) offering basically a three month free trial. When we offered small hosting account packages, we offered 12 months free Gets alot of people to try without risk, and almost all stay on for paid hosting.
You *must* have some serious fraud prevention measures in place if you offer something like this. Don't rely on AVS, etc. to handle it for you. Giving away free/trial hosting is VERY risky...but if done right and you can afford it, it can work.
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