Quote Originally Posted by Боб Уайтман View Post
Strange... Maybe, it is regional then? In Samara people do say "помидора" as a mass noun.
Just checked in Yandex. I was right! It's a regional feature of Russian.
Proof-links for Samara: Эх Самара Городок)
Saratov: 2. Нормативное употребление форм слов
and Nizhniy Novgorod: Салат "Мужской каприз"
(try searching for "помидора" within those web pages, it explains everything).

I believe it looks like a common feature of Volga Region. I am not sure for other places though.