I had signed up for text-link-ads in January (not sure) and waiting for links to sell. But you know I had no luck and just waiting. It was April someone or more than people bought links in my posts. For April month I get paid in May by TLA and for May I get paid on first of June. And you know April was bad but May was worst for me in traffic and adsense earnings. It took me two months to figure out why I had penalized and still. I forget to mention about paid links in my one of post. I had installed a plugin from TLA and Google had no objection but when links sold out Google had. For earnings June was going very well, I earned two times higher in just seven days comparing to April and May earnings form TLA. But I had to make a choice and I made one and removed TLA plugin. I hope everything will be fine very soon.
It is not just TLA, there are so many sites that are buying and selling links. You can make good money by selling links but if you do not depend on Google, if you do you are going to penalize for sure.