Here is some more thinking...

I've considered a wide range of options, including points systems, bidding, counters and complex ratios to determine how many pixels an artist can reserve. Trying to balance a system that encourages participation and excitement with casual involvement and collaboration is not easy.

The answer is to make it really simple but compelling

What do you think of these rules?:

1.Each contribution must be 300 pixels high 2.It is added to the right of the previous work 3.The width of the work is allocated 10 pixels at the time of submission of the previous piece 4.A counter counts down from the current time period between submissions divided by your Post Rate (or hog factor) to the next addition of 10 pixels to a maximum of 100 pixels wide. 5.Post Rate (Hogfactor) is the number of other artists submissions between your last one and the current point - if you do two in a row, it is 2:1. 6.You have 2 hours from reservation to post - lasped or cancelled resevations return all users to the allocation as when it was reserved.

Example There have been 6 other submissions between your last submission and the current one just posted. Your Post Rate is 1:6. 1 hour has passed since the 5th submission so you face the choice of accepting the 10 pixel limitation and reserving it now or waiting for the counter to count down 1/6 hour (10 minutes) for each addition of 10 pixels. If you accept the the 10 pixel allocation and quickly submit, then you have only to wait as long as it took you to submit for the allocations of more pixels. The downside to this is that someone with a postrate of 10 will almost instantly have a full compliment of 100 pixels to reserve. If noone take up this opportunity and you get to reserve and post a full 100 pixel image, you will then have to wait twice as long for the next lot of allocations as your hog factor would be 2:1 .Even if you did it in 10 minutes, you would have to wait 100 minutes for the next full allocation. Basically these rules are designed to encourage you to post, but not too much, wait around for others to post, refresh often, see what they are doing, and come back to the site occasionally (daily?). If the site is active, your opportunity to contribute will be increased in time and scale, but limited by the fact that it also advantageous to others, who may make reservations before you. there becomes an incentive to accept smaller allotments, or you might miss out. There would also be some pressure to contribute quickly for the sake of others who were waiting to participate. If the site is slow, you can afford to relax, contemplate your contribution, wait for the allocation you desire and return more occasionally to check on progress. This also allows for some time counters on the interface that could be quite exciting. What do you think - close to the mark? Steve