AncestryDNA

 
Has tested Y and mtDNA in the past.
 
Testing kits are now offered in 36 countries, as of December 2018.  The listing of countries can be found here.
 
Does not accept DNA transfers.  
 
As of November 2018, the company claimed to provide access to approximately 10 billion historical records and to have 3 million paying subscribers.[1]  They have 16 million DNA profiles.7  As of 14 July 2020 they have 18 million users that have tested their DNA and opted into cousin matching.10
 
Testing is done via a saliva sample.
 
Geneticists test about 700,000 single nucleotide polymorphisms (SNPs), or locations, on the genome to estimate ethnicity, said Crista Cowan, a corporate genealogist at Ancestry.com. To gauge accuracy, every one of the snips must meet a 98 percent quality measurement; otherwise, the sample must be resubmitted. DNA samples are then profiled against a "reference panel" of people from 26 regions encompassing nearly the entire world, she said.[2]
 
Matches must share 1 segment of 5cM or more.  This could falsely identify distant cousins as cousins.[3]
 
Shared Matches only works for 4th cousins or closer.[4]
 
While Ancestry does test the X chromosome using approximately 17,000 – 20,000 SNPs, it does not use the X-DNA when comparing individuals in the database.[5]
 
Procedures & Presentations:
 
 
 
2017 Salt Lake Christmas Tour Presentation and Speech
 
 
AncestryDNA and Subscription Features[6]
Some features of AncestryDNA® are available only when a public family tree is linked to a test. These features include Shared Ancestor Hints, DNA Circles, and New Ancestor Discoveries.
 
As a benefit to the early adopters of the AncestryDNA® test (people who purchased it before October 2014), we’ll continue to provide access to matches’ family tree data, with or without a subscription.
 
Ancestry acquired the DNA results of the customers of Relative Genetics and incorporated them into their Y and mtDNA database.  In June 2014, they announced the future dissolution of that database, giving customers three months to access their data and their matches.  A few days later they suffered a denial of service attack, destroying the search function for that database.  Ancestry also owns the Sorenson database and could have combined their database with that of Sorenson.  Ancestry began selling autosomal DNA tests in 2012.8
 
Downloading Ancestry Folders - The functionality is available until August 31, 2020.
 
 
Ancestry announced 5 Jun 2014 the retirement of Y-DNA & mtDNA (aka LegacyDNA) & their sites of Mundia, Genealogy.com, MyCanvas & MyFamily.9
 
ThruLines
Automatically finds Common Ancestors out to 5x great-grandparents.
Can see Private Trees; searches for a common ancestor in your tree and someone else's tree.

[1] Wikipedia (http://www.wikipedia.com), “Ancestry.com,” rev. 6 Dec 2018.
[2] See "Rockford native left in 'total shock' after receiving Ancestry.com DNA results," rrstar.com, posted 29 Nov 2016 (http://rrstar.com : accessed 3 Dec 2017).
[3] See Blaine T. Bettinger, The Family Tree Guide to DNA Testing and Genetic Genealogy (Cincinnati, OH. : Family Tree Books, 2016), 103, AncestryDNA.
[4] Bettinger, The Family Tree Guide, 114, AncestryDNA:Shared Matches.
[5] Ibid., 128-129, How The Test Works.
[6] See "AncestryDNA and Subscriptions," Ancestry.com, (http://www.ancestry.com : accessed 16 Dec 2018).
7 See "A Court Tried to Force Ancestry.com to Open Up Its DNA Database to Police.  The Company Said No," buzzfeednews.com, buzzfeednews.com : accessed 5 Feb 2020).
See "Ancestry Destroys Irreplaceable DNA Database," DNAeXplaied - Genetic Genealogy, dated 2 Oct 2014.
9See  "Ancestry.com Officially Retires Y-DNA and mtDNA Testing," Your Genetic Genealogist, dated 5 Jun 2014.
10 See "Ancestry DNA Tops 18 Million Users," LostCousins Newsletter, dated 14 Jul 2020.