Ah, but these days, as a porn site you've got to compete with thousands of others.

It's not "will the audience look for porn", it's "Why will they choose your porn over someone else's?"

(Likewise, it's not "Will the audience look for an action-adventure show", it's "Why should the audience choose YOUR action-adventure show?")

That site caters to a specific fetish, female domination. There are not thousands of sites competing with it.

Most successful porn sites cater to a specific fetish, instead of a bucket of random porn.

He needs to find his target market. Not sure who it should be, though.

Please google your tagword. Better yet, google Female domination Porn. You're going to get a lot. If you go out and use the actual jargon, Femdom Porn, you're going to get quite a lot as well.

Point being: there may not be thousands of sites competing, but when the search returns over a million sites and its nearly straight femdom out to the thirteenth results page (and likely beyond)...I'm going to wager that you didn't do that very simple bit of research, a google, before making such a declaration.

"hacker news porn" returns over 286,000 results...

As you yourself said, the actual jargon is "femdom porn", not "female domination porn", or even simply "femdom".

By adding "porn" to any keyword search, you will get many extraneous results (see "hacker news porn" above).

Most importantly, these "alot of results" all have affiliate banners to the same handful of "femdom" sites.

Next time, try looking at the actual content, not just the Google results. I should have taken you up on your wager!

Femdom being one of my fetishes, I rather beg to differ on the statement that there are only a handful of femdom sites.

I will cede that there are a few fantastically successful ones, like I suspect in most media, which are rather strongly linked to...