Does adding directory to website increase ranking, and is it worth doing it. For exmaple having loan site www.example.com and adding directory here www.example.com/directory. and in the directory only having finace realte site to it.
Yes it will help. Just be careful who you link back to. Make sure the sites that you link back to are related to your site and will be valuable to your visitors.
Backward links have some benefit but one way links are better. This is worth a try though I would be hesitant to go down this line to much for return links, if this is easy and cheap for you to do maybe worth it but I would focus the time on one way links in relevant sites to your site.
Definately this idea will work and it increase back links of your website and visitors too. Ranking will also improved.