Lately I found this widget at several blogs and site. It turns out to be a widget that enables readers to give a tip in exchange of a link back to your blog. It is an online tipping system call ScratchBack. The widget allows you to accept tips and give back links or images in return and the links are nofollow. That means those links do not pass Page Rank. You are able to set the price of the tips and the minimum amount is $1. Once you received tips more then $25 then you can initiate payment through PayPal. At this moment the commission structure is after the PayPal fees, publisher will get 90% of their tips. Any changes about the commission structure will be announced on ScratchBack blog. In my opinion that is still consider a fair deal. Surely the site needs some money to keep on running and sustain. This is better then having to set a certain amount of fees for using it.
I think this is better then donate or “buy me a beer” as some credits are given back to tippers. So the question is that can it be use to make money online? Well, that depends on how much you set the amount for the tips. You can set $25 per tip but then you need to evaluate your blog to see if it worth the price. I think this widget can be use as a method for your readers to say thanks or appreciate the work you done. So $1 will just be nice for my price.
P/S: ScratchBack is no longer available.