I think that might have been me, actually. And I’ve begun doing that.
My theory is that it’s easier to dominate a micro-niche than it is to take a slice of a very competitive area.
But it wasn’t niche casinos, actually, it was niche portals. An example might be to build the biggest and best authority site on the web for Spanish 21. (Just brainstorming off the top of my head–that might actually be competitive.) “Blackjack” and “online blackjack” are hard to rank for…