I don't know how large the original DoTA community was or how large it is today, but the the genre became much more largely popular with the advent of the free to play game LoL, which attributed its game style to DoTA.

What I mean to say is, that many people who are familiar with the game/genre could have never played or touched WC 3.

Interesting tidbit, the LoL website does not mention the DOTA acronym even once. According to Google, the acronym only appears on the forums, on user posts - and from the first dozen results page or so, is almost always used to directly mention the specific games named DOTA, DOTA 2, and Blizzard DOTA, instead of being used as a generic tag or the genre name. So, it seems the LoL developers and community - or, at least, the players that post on it's forums - aren't using the DOTA name in any way that could suggest it's a description for the genre.

As said in the article, LoL players which afaik is the largest game of it's kind (something like 30m), refer to the genre as Multiplayer Online Battle Arena, or MOBA. They indeed, never refer to DotA as the genre.