This document discusses different types of links and their impact on search engine rankings. It explains that there are two main types of links - paid/rented links and permanent links. While paid links can influence PageRank in the short-term, search engines like Google are working to discount these types of links. In contrast, permanent links acquired through content marketing like article publishing are less likely to be penalized since they are placed on new pages starting with PageRank 0 and can organically increase in PageRank over time as the page ages. The document recommends article marketing as an effective link building strategy that is more positive in Google's algorithms.