For SEO reasons, link building is highly required for a website to increase its Page Rank.  Most people rely on a one-way or two-way link building with web directories.  Since, there are plenty of webmasters that are willing to add a site in their web directories.  However, an interesting fact is hand-edited directories are preferred over automated directories. 

 

An ideal example of such a directory is SlackAlice Web Directory.  Whether it is for paid or free submissions, one has high scope of increasing their site’s web presence by adding their site on www.slackalice.com.  All entries are manually checked by editors before an entry is accepted.