The internet is full of directories, and full of people offering services to include your site in all those directories. They are of little use for SEO today, certainly when compared to Social Media as an SEO tool.
Going back just a few years businesses were going mad about directories. Online budgets were being spent on premium placements and button and banner advertising. Things change however. Directories no longer hold the same power. Google have even said that they will not be placing as much emphasis on dmoz (the mother of all directories). This is because many sections are without editors and there has been widespread criticism of some editors. It is something I noticed myself. It can be extremely difficult to get a site listed on dmoz. At best it can take months.
Am I saying not to bother with directories and to concentrate instead on Social Media?
Not quite. When it comes to Google Local, the map results for businesses, local directories seem to hold some weight. This is because Google is slow to trust submissions to Google Maps by businesses. If the business address given on your contact page is the same as that listed in various local directories then it builds that all important trust. It also helps to identify you as an actual local business.
The links from directories still hold some weight too, depending of course on the directory. They just don’t help your SEO as much as they once did.
For my money, I’d rather invest in SEO training and in particular Social Media training than on expensive banner advertising on directories.
Niche directories are probably more useful than general directories now too. This is because nobody really uses directories to find sites any more. Search engines are just fine for that. A niche directory however will get you targeted, specific results, and probably ranks better for whatever it is you are searching for than a generalist directory. A good niche directory will hold information on the field too, rather than just being a list of businesses/ websites.
By the way, don’t bother with paid directory inclusion services, they are likely to do more harm than good!