[nurik]

I see your point. However, jf you have a smart solution that's worth buying, people will buy it over and over again and even when it seems "cheap" it could generate significant revenue (just like the songs etc. on itunes)...

[bkyan]

I totally agree with you on those favors where the deliverable can have multiple buyers. I tend to think of most favors as being one-offs, however.

[nurik]

I think you are right. If you look at Amazon's site for small digital tasks most "favors" are one-offs: http://www.mturk.com