A common question asked in all the forums is:  “What are the best directories to pay to submit my website to?”

If you ask this, you’ll get lots of responses.  But generally, the responses tend to list the directories that are most popular or that are owned by the person answering the question or his or her buddies.

There really is a lack of objective evidence as to which directories are truly good.

Fortunately, the folks over at Seomoz have recently developed a page strength tool.  While it also looks at .edu and .gov links, it takes a much more wholistic view of the website than ILQ does, and probably is more representative of how Google views websites (and directories).

According to Seomoz, the page strength tool is “a better metric to quickly assess a site / page’s relative importance and visibility.”

AFAIK, no one has comprehensively applied this tool to the directory space, so I’ve gone ahead and done this.  I’ve checked the page strength of all the paid directories listed in Bob Mutch’s comprehensive listing and then ranked them in order of page strength.  (If you would like your directory added to this list, please contact me - there’s no charge for this.  Your directory must have a minimum page strength of 5).

Update:  Despite being hung over, Randfish blogs about this.

Update:  Prices added next to each directory (thanks to jestep for the suggestion).  Prices are in the format ($first / $second).  First price is for a basic submission and the second price is for an express or featured submission.  Note that several of these directories also have free submissions if you’re willing to wait many months for review.

Update:  The folks at webrankinfo.com blogged about this, and created a list of French web directories sorted by page strength.

Update:  Michael Duz does a study calculating the correlation coefficient between page strength and page rank.

Update:  Softduit.com has ranked blog directories by page strength.  The first thing that strikes me about this list is that there are a large number of very strong blog directories, which may be a function of bloggers general generosity in linking out.

Update:  There has been some debate about whether a directory located on a sub-domain or folder should use the page strength of the domain itself or the page strength of the sub-domain or folder.  The issue boils down to how much value is transferred from the domain to the subdomain or folder.  Obviously, only the search engines know what the answer to this is, and it likely varies over time and between search engines.  However, the fact is that at least at the present time, sub-domains and folders do appear to inherit a good chunk of the main domain’s value, so when a directory is on a subdomain or folder, I have chosen to list the page strength of the main domain.  I also put the actual directory home page’s page strength in brackets after the listing.

Without further ado, below are the strongest directories (last full update June 24, 2008:

Page Strength 10
http://www.dmoz.org/ (free)
http://dir.yahoo.com ($299 per year) (Directory subdomain has page strength of 10 as well)

Page Strength 9.5
http://www.business.com/ ($199 per year)

Page Strength 8.5
http://www.botw.org/ ($79.95 per year or $239.95)
http://bubl.ac.uk/ (free)

Page Strength 8
Directory.v7n.com ($49.95) (Directory subdomain has page strength of 6.0)

Page Strength 7.5
http://www.ezilon.com/ (free / $69)
http://www.iwebtool.com/directory/ ($9.95 per year) (Directory subdomain has page strength of 4.5)

Page Strength 7
http://www.avivadirectory.com/ ($49.95 per year / $74.95 per year)
http://www.familyfriendlysites.com/ ($9.95 / $49.95 per year)
http://www.goguides.com/ ($69.95)
http://www.romow.com/ ($45 / $90)

Page Strength 6.5
http://www.2yi.net/ ($15.95 / $64.95)
http://www.bloggeries.com (unknown)
http://www.dirjournal.com/ ($59.95 / $99.95)
http://www.elib.org/ (60 Euro / 150 Euro)
http://www.gimpsy.com/ ($40)
http://www.index-it.net/ ($25)
http://www.joeant.com/ ($39.99)
http://www.maxlinks.org/ ($12.50 / $49.50)
http://www.mozdex.com/directory/ (unknown) (directory folder has page strength 5)
http://www.mygreencorner.com/ (free / $25 per year)
http://www.relmaxtop.com/ (unknown)
http://www.skaffe.com/ ($49.99)
http://www.tygo.com/dir ($39.99) (directory folder has page strength 5.5)
http://www.webworldindex.com/ ($25)

Page Strength 6
http://www.allinfodir.com/ ($26.95 / $69.95)
http://www.allydirectory.com/ ($12.95 / $59.95)
http://www.busybits.com/ (unknown)
http://blogannounce.info/ ($9.95 / $16.95)
http://www.browse8.com/ ($35)
http://www.cascandra.com/ ($11.95 / $29.95 per year)
http://www.dmegs.com/ (free / $9.95 per year)
http://www.domaining.in/ (free / $25 per year)
http://www.ebjuris.com/ ($10 / $20)
http://www.gii.in/ (unknown)
http://www.incrawler.com/ ($24.95 / $49.95)
http://www.kahuki.com/ ($19.95 / $49.95 per year)
http://www.lobolinks.com/ $22.99 / $36.99 per year)
http://www.onlinewide.com/ ($34.95 / $69.95 per year)
http://www.prolinkdirectory.com/ (free / $9 for 3 months)
http://www.rakcha.com/ ($29)
http://www.sevenseek.com/ ($40 / $99.95)
http://www.site-sift.com/ ($29.95 / $99.95 per year)
http://www.szab.net/ ($16.95 / $39.95)
http://www.top5jamaica.com/ (free)
http://www.uksmallbusinessdirectory.co.uk/ (49.99 pounds / 99.99 pounds)
http://www.uncoverthenet.com/ ($59 / $199 per year)
http://www.ventedoy.com/ (bid for placement; min $5)
http://www.webahead.net/ ($20 / $50)
http://www.wowdirectory.com/ ($43 / $65 per year)

Page Strength 5.5
http://9ug.com/ ($5.99 / $19.99)
http://www.abilogic.com/ ($9.95 / $39.95 per year)
http://www.anthonyparsons.com/ ($10 / $30)
http://www.apahcinc.org/ ($34.95 / $69.95)
http://ask-dir.com/ ($47 / $69 per year)
http://authoritydirectory.com ($4.95 / $19.95 per year)
http://www.authoritydirectory.com ($4.95 / $19.95 per year)
http://www.blazemp.com/dir/ (bid for placement; min $49.95)
http://blogaboutmysite.com/directory ($14.95 / $55.99) (directory folder is pagestrength 5)
http://blogtagstic.com/ ($9.97 / $29.97)
http://www.citystar.com/ (unknown)
http://www.dirwizard.com/ ($19.95 / $59.95)
http://www.ebusiness-directory.com/ (unknown)
http://www.emillie.net/ ($24.99 / $39.99 per year)
http://www.enquira.com/ ($29)
http://www.e-topic.com/directory/ ($19.95 / $34.95) (directory folder has pagestrength of 4.5)
http://www.global-weblinks.com/ (free / $40 per year)
http://www.idk.in/ ($14.95 / $49.95 per year)
http://www.kwikgoblin.com/ ($24.95 / $59.95)
http://www.linkopedia.com/ ($9.99)
http://www.linksjuice.com/ ($24.97 / $49.97)
http://www.linkwith.us/ ($34.95 / $69.95 per year)
http://www.makeasearch.com/ ($4.95 / $19.95)
http://www.map100.com/ ($10.95 / $91.95 for 180 days)
http://www.nobledirectory.com/ ($25 / $50)
http://www.nzpages.co.nz/ (unknown)
http://www.pegasusdirectory.com/ (free / $17)
http://www.photarium.com/ ($7 / $19.97)
http://www.qango.com/ ($15 / $55)
http://www.seoma.net/ (unknown)
http://www.vxbox.com/ (3 Euro)
http://www.web1directory.com/ (unknown)
http://www.webotopia.org/ ($14.99 / $29.99)
http://www.zorg-directory.com/ ($14.95 / $59.95)

Page Strength 5
http://www.123kidzarea.com/ (n/a)
http://www.alikedirectory.com/ ($25.99 / $49.99)
http://www.alivedirectory.com/ ($49.95 per year / $74.95 per year)
http://www.businessseek.biz/ ($10 / $20 per year)
http://www.ensuredirectory.com/ ($14.95 / $34.95)
http://www.excellentguide.com/ ($24.99 / $79.99 per year)
http://www.fullofsearch.com/ ($34.99 / $54.99)
http://www.qoobe.org/ ($7 / $20)
http://www.homesalez.com/directory/ ($49.95 per year) (directory folder has pagestrength of 4.5)
http://www.linkcentre.com/ (49.95 Euro per year)
http://www.linkspub.com/ ($15 / $40 per year)
http://www.massivelinks.com/ ($24.99 / $59.99)
http://www.maxdirectory.eu/ ($9.50 / $19.50)
http://www.postdotcom.com/ ($11.95 / $39.95 per year)
http://www.umdum.com/ ($40 / $100)
http://www.web10.ws/ ($24.95 / $59.95)