So you want to buy links in directories to get your sites ranked in SE. You search for directories and lo, a million results come up. Before you decide where to buy a link, there are some questions you need to ask yourself.

Who links to them?
Does the only link to the directory come from the link pages of Viagra sites? If yes you probably need to stay away. With SE emphasizing the quality of links this ha become even more important. Look for the incoming link quality before you buy a link.

Whom do they link to?
Can any spammer just buy a hundred outbound links from the directory? Do they accept automated submissions? SE give a very high value to outbound link quality and appearing in listings along with obvious spam sites wont do you any good.

Are the category pages crawled?
Does the page you want to get listed on even exist in SE databases? Many poor directories have only homepage crawled by SE. If the page your link appears on does not have a presence, why bother paying for it?

How frequently is the directory crawled?
Does the Google index of the page show six months old data. Or does the site get crawled frequently? The faster SE crawl a site, the more they trust it. And that is where you want to get listed.

What is their ad ratio?
Do they fill their category pages with Adsense ads? Will human visitors find any value in the directory? You may want the link just for PR, but with usage data becoming important, you want to buy a link that is useful to human visitors.

Is it unique?
Is it just a DMOZ clone? Or did the directory editor compile a listing of truly useful sites and you can get a listing alongside them? Needless to say, the more unique the content, the better is the directory.

Is it relevant?
If you sell autos, a link in an auto directory is much more valuable. If you sell to a specific geographical area, buying a link in a regional directory makes much more sense.

What is their PR?
Page rank though highly discounted now, still holds a value. While I would not recommend getting a link based just on PR, do not overlook PR while choosing a directory.

Keeping these points in mind should help you decide which directory to choose.