In the beginning Google created an Algorithm, and it was good. It was based on sites linking between each other, creating a “web” of pathways for users to follow.
Business practices have included “paid” advertising for many many many years. Links today are being purchased for advertising purposes. Google doesn’t like. Why is it now that Google is wanting webmasters to nofollow and to not take money for links that allow users to follow. If you haven’t heard, nofollow is a Link Condom, it protects Google’s Algorithm from skanky, whorish, God Forbid – “Paid Links”.
Google is wanting Fake Link Pimps to tattle on sites with paid links. “Matt Cutts a Link Pimp?“, is a fun Post with a pic of Matt C. in Pimp Clothes.
Just like prostitution paid linking will simply go low profile/underground. As Google has success penalizing paid linking people will simply stop using visible services like Text Link Ads and find new ways of doing business. Buying and selling paid links will become more sophisticated and/or secretive but it won’t disapear.
I am not suggesting to hide the links you are being paid for with JavaScript or AJAX as that is probably not what was the expectation from the purchaser. But if you have Affiliate links or other links that you are not worried about passing “link value” then it might be a technique that could be used.