donations vs. advertising

I'm going to try something to reduce the amount of advertising I need to do to keep this site running in its present (growing) form. I've added a paypal donation button to the side bar here and there are some scattered throughout the timelines site. What I propose is that I will set a goal amount, which will be the average amount of revenue I get from affiliate advertising and each month as doanations approach that goal I'll reduce the amount of affiliate advertising accordingly the following month. So if The monthly goal is set to $20 and I get $10 in donations I'll cut the affiliate advertising in half. That will be top and bottom banners and most items in the menu bars on the timeline pages.

How the mechanics will work is that I will have 'dial' that can be set on the template program that will determine tha amount of advertising to show as I update individual pages. As the donations come in for a given month I'll turn this dial up as I'm updating. So if i get a donation for $1 on the dial will be set to 1/20th and all pages will have that reduction. Then, if a couple days later another donation comes in for an additional $5 the setting will be at 6/20th. This doesn't seem particularly even because not all the pages will be changed, but which ever changes are changed will remain that way until they are updated again. So it will be slow to reduce slow to raise. At the end of the month the setting will be brought back to 0/20th.

That is the current plan. I will be working with paypal to get the information worked out to make reporting automatic either in this side menu or another active place on the site.