However, directory links show in your Alexa profile and if you are building an site that aims to be an expert site for its topic or a blog that you may later want to sell advertising on, then building up links of this type is a good strategy which will give you credentials if someone fast scans your Alexa profile. Adsense cannot compare for clicks in most cases with regular sponsored advertising from individuals.

There are however people who are totally snobby about advertising and intensively dislike it. When you are link building, having Adsense or any form of monetization on your site may hinder your efforts for the exchange of links with directories, serious bloggers and authority sites. However good your content is, having advertising aside of it, is akin to sacrilege.