what is directories?

Nothing I can say they already explain it well!

Directory is one of most important part of SEO and now we can't approced with it. According to big G! backlink is required to make you site trusted but remember to exchance link with only relevant site. We can't alway make link exchange with relavent site cause most of site will not gonna accept you proposal of link exchange. So only the way to make bump your link on the web is through directory. Some directories are niche and some are mixed categories. Submit your site every to at least 5-10 directories to get good response by SE. Anyway, just believe at only directories rather than other one.

DMOZ, Yahoo and joant are the best directories but the latter two you have to pay for.

A directroy is website, which provide free or Paid Backlines for your website

directories are easiest way to get back links, which is important for Page ranks

Shortly saying , web directories were used by you and me before the search engines gain so much authority, after the engines gained the power they have today directories are used to gain authority within the engines like google and yahoo.

I is a network designer, we are referring in google to our commanding officer. In the main catalogue part - Economy and trade / real estate - 343 places have already been enumerated. If you watch, to part - area / U.S.A. every state / Alabama / real estate of catalogue those area those - have 11 websites enumerate.

In directory sites you can gain lots of backlinks but it depends on that directory, If this directory have PR.

its very strange for me that if any web master dont know about directories and the part of directories in search engine

Directories are directories easy as that.They help with backlinks so you can get your page rank up.My experience their not so great for traffic.Make sure they are dofollows so you gain a link.directory critic.com is the best.
They have thousands of free directories and they tell you their page rank and if it's a dofollow or nofollow.