Very interesting site you've put up here. I've always been interested in Genealogy metrics, especailly those for genealogy software.
I'm curious how you select what sites are "genealogy" to include in your metrics. I do see very few software sites listed.
There's never been any "hard" evidence of which are the most popular programs, there's only been claims by the developers, so it would be great to see an Alexa list or something maintained by someone.
If you need a list, I maintain the GenSoftReviews site at: http://www.gensoftreviews.com
(currently 473,631 on Alexa) where I list 381 different programs, including 77 online sites.
A very quick scan of some of the better known downloadable programs gives the following rankings on Alexa:
148,047 - FamilyTreeMaker
437,666 - Legacy
559,954 - Roots Magic
724,352 - The Master Genealogist
992,959 - Reunion
2,834,753 - Brother's Keeper
Personal Ancestral File comes in at 12,280 because it's web page is part of www.familysearch.org
For a few of the more notable Online sites for maintaining your family tree, I quickly found the following rankings on Alexa:
1,205 - Ancestry Online Tree (ranking includes all of Ancestry.com)
3,791 - Geni
16,757 - One Great Family
112,172 - Kindo
120,091 - Tribal Pages
136,424 - Kindred Konnections
178,639 - GenCircles
275,556 - Genetree
453,678 - Dynastree (formerly: It's our Tree)
2,413,153 - Famillion
Maybe you, or someone else can maintain a complete metrics for these two groupings. I'm sure people will find them interesting and useful.
p.s. My own program Behold at http://www.beholdgenealogy.com
has an Alexa rating of 652,765