Jimmy Wales wrote:
I would be very opposed to turning "Thomas Jefferson" into a disambiguation page like this:
"Thomas Jefferson is the name of at least two people:
[[Thomas Jefferson (president)]] - 3rd President of the United States
[[Thomas Jefferson (plumber)]] - plumber in Des Moines, Iowa from 1943-1947, subsequent whereabouts or activities unknown"
(We would usually make a [[Thomas Jefferson (disambiguation)]] and link to it from the top of the president's page, since the degree of fame is so different.)
But I really think that the confirmability rule helps with almost all cases like that.
Beware of genealogical publications though. My mother's side of the family is Mormon, and they have lots and lots of confirmable people and dates.
So I think you do need some notion of importance. One of the ideas I've thrown out is to count the people to whom the article subject matters in some way; London is in because it affects billions of people, the cat in the tree is out because it only affects the people on the street and the writer for the newspaper, 100 people tops.
I've been testing this mentally on various topics, and a number somewhere between 500 and 5,000 seems plausible. I don't think it would make sense to try and pick a number and impose it as a rule, but it makes a good sniff test for things that seem obscure. For instance, most consuls of ancient Rome are very obscure today, but once upon a time they ruled millions, and are for that reason encyclopedia-worthy.
Stan