[Simon]

My stand on this is the same as always. A cookie should never expire... anything shorter than that, someone is taking your traffic and refusing to pay you for the surfer you originally sent to them.

If a webmaster sends someone to a tour and he gets interrupted by something before he can join but goes back later, or tomorrow, or next week, or next month, or whenever, I think the original webmaster who sent that surfer deserves a commission if he was the last affiliate who sent that surfer to the sponsor's tour.

Unless a surfers clicks another affiliate link which overwrites your cookie, there is no good reason for a cookie to expire aside from sponsor greed. The shorter the cookie life, the more the sponsor is demonstrating their greed. The sponsor is basically saying to you, "this is what I think all of your work is worth."

All traffic has some cost and therefore some value, even if only the time and work that went into building the pages or writing the posts which originally convinced the surfer to visit the tour page. Short cookies seem to say that the sponsor doesn't believe our traffic has much value to them. Which makes me think it may not be a very good idea to send our traffic to them either.

Seriously, is there any reason to use short cookies besides depriving the webmaster of an earned commission as early as possible?