I suggest you look at the citation as a whole, not just the particular isolated feature of "repository". If ancestry is already mentioned in the citation, it is totally unnecessary to repeat it again and again in the citation.
Let's give an example, say, of an 1850 census entry coming from the census at ancestry.com:
Ancestry.com, 1850 United States Federal Census (Provo, UT, USA, Ancestry.com Operations, Inc., 2009), www.ancestry.com
, Database online. Year: 1850; Census Place: , Butte, California; Roll: M432_33; Page: 12A; Image:.
I suggest that having the text string "ancestry.com" 3 times in the citation is ridiculous, the text string "database online" is redundant and ridiculous (knowing that the info coming from ancestry already says the database is online), ancestry's address "Provo, UT, USA" is easily findable and equally ridiculous, the text string "census place" is obvious and ridiculous. And, note the image reference was omitted. Which could lead to this citation, which is a more appropriate citation, IMHO:
1850 US Federal Census, www.ancestry.com
, 2009, Butte, California; Roll: M432_33; Page: 12A; Image: xx.
This is of particular significance to those who may wish to publish their findings in a paper format, eg a genealogy (register) report on paper (where endnotes in a "normal" length report can generate hundreds of pages of citations). This is not so significant for an on-line presentation because on-line trees typically have unlimited resources to include all of this extra citation "garbage" in their citations.
Social Security DataBase:
Ancestry.com, Social Security Death Index (Provo, UT, USA, Ancestry.com Operations Inc, 2010), www.ancestry.com
, Database online. Number: ; Issue State: California; Issue Date: Before 1951.
Besides the above comments, does not include the date of the latest update of this particular index:
could be shortened to:
Social Security Death Index, www.ancestry.com
, updated 02/17/2010, Issue State: California; Issue Date: Before 1951.
Unfortunately, since I still use ancestry for my main research source, I can't do anything about these citations because the next record from 1850 (for example) will replace an "edited" version of the source with the "garbage" citation of the next 1850 census record I merge into my database.
And.. I have more pressing demands on my time than to correct all of the dumb ancestry source & citation "garbage", so I move forward putting up with them.