Thanks for introducing your readers to adCause.com. I just want to touch on your statement:

"This is where I draw the line. I am obviously not adverse to advertising as I have admitted to selling my background, and this very blog carries ads in the right column, but I am opposed to ads being forced on a person. When I sell my background, it is just that, a background image. It does not change the way Twitter works in any way, and no one has to read it that doesn’t choose to."

Selling your background is no different then selling a spot in your twitter stream. "It does not change the way Twitter works in any way, and no one has to read it that doesn’t choose to." – That is completely not the case, as we offer a simple opt out: Quit following that person. A background is a blatant visual ad, where as our ads blend into the twitter stream, much less obnoxious.

We let users give some or all of their profits to a good cause, which none of the other services offer. We want to improve the twitter community, not degrade it. You get to choose every advertiser, and how often the ad appears. Companies like twittad offer little to no control over the users ad space, and how often it appears. With zero click through, there is little to no analytics on how effective those background ads are.