Clarification for those not in the business -
PPC (pay per click) links are the sponsored links at the top of the page, managed through adwords; have the bejesus tracked out of them.
SEO (search engine optimisation) links are put there by the algorithm that Google obfuscates to stop SEMs (search engine marketers) gaming the system too hard.
For the sake of completeness, Google Shopping is PLA (product listing ads) or LIA (local inventory ads) and also paid but, certainly where I work, are treated as distinct entities for the different knowledge required in managing the adwords accounts.
For the sake of further completeness, these are entirely seperate again to the banner and video ads that we all know, love and block.