Is it OK  to sell links off your website?

You worked so hard and your site finally has PR5 (for the sake of argument). Should you be able to sale links to offset the price you paid for getting your website to be so popular?

I think, Why not? If Google sells ads with AdWords helps and making billions on that business. Why can’t I  sell ads off my website?

For some reason public opinion is different on the fact that Forbes has been in business selling links on their site. Again, what is a big deal and why people so stressed about it? If the Search Engine concept did not exist Forbes would not be selling these links to begin with.

I am amazed by the fact that “Forbes received a notice from Google encouraging Forbes to remove the links that could be intended to manipulate PageRank.”

It looks like the Search Engine giant Google is in business of censoring what links we can put on our websites. That sounds like total absurd to me. What would be next?