With the recent Google Pagerank changes, there has been many discussions since some pages in the Yahoo! Directory pages PageRank have appeared to decrease.
Some webmasters who frequently post on SEO forums are under the impression that they have wasted up to $299 at a time.

It costs $299 a year for a website to be reviewed and included in Yahoo!’s directory, with the page that a link is listed on now having a low PageRank, you could forgive people for thinking that the money they have spent hasn’t been worth it.
However, it is not that simple. Many webmasters will tell you that passing the review process and being included in the Yahoo! Directory is an achievement that the toolbar PageRank doesn’t reflect.

The Yahoo! Directory tends to only include websites of a high quality, a low PageRank within the directory doesn’t reflect the true importance of being listed there.

Google knows that the Yahoo Directory is full of quality websites and those that do make it through the reviewing process can not be considered to be spam. This is a huge vote of confidence especially if your site is brand new.
Using this as an example, it does prove that there are other elements to consider when purchasing links and not just PageRank.