Emulators don't only play roms of pirated videogames. A very large part of the emulation scene is also about using the old game engines to create mods and new games altogether; there are thousands upon thousands of legal user-created games out there.

As there's nothing illegal about emulators, there is obviously nothing illegal about selling your own program/app. Just because the app is capable of playing pirated tech doesn't mean that's necessarily what it was created for, and all the contents are legal. You can't make it illegal to sell one's own work.

Well google and apple should take them down.

No, it's not.

Also, why would you want that?

Emulators are indeed legal, and there's plenty of other uses for it than just playing "commercial" games, as others mentioned before me. It also plays a very important role in the preservation of gaming's history, as evidenced by MAME's extraordinary efforts, for example. You certainly can't expect much in this area from publishers, either because of being organizations for profit, or because of having to deal with copyright limitations...

From what I know, the case of Bleem! vs Sony was decisive in this whole context:
http://en.wikipedia.org/wiki/Bleem!

Now, how all this applies to app markets... I'm not sure. Most emulators are free, so if someone is using open source code for profit, that's not cool... I don't know what is exactly being sold here.

No if Nintendo etc want them taken down they just have to ask, things get taken down for copyright violation all the time. But it's up to the copyright holders to hunt the stuff down.

Besides there has been little success in suing people over emulators in the past, as a general rule emulators themselves are legal as long as they don't violate any copyright themselves. It's the ROMs which are illegal.

Emulators are not illegal. Nor are ROMS. They are created as a convenience for the person who owns the actual hardware/software. People just misuse the technology.

in a word, no no one should be sued for distributing an emulator.

Emulation is 100% legal. There should be more of it. If I buy a game I should be able to play it on any device I have the geek knowledge to do so. When I buy a game I own it, not just a license to use it once.

huh? I thought the removed the emulators.

I knwo the best ones you have to get the apks yourself.

nothing against emulators but Google is really shitty in copyrighted material released in their play store.. Apple at least tries to screen most apps but there will be always a few that get through but Google is just publishing everything untill someone noticed...

https://play.google.com/store/apps/details?id=com.supermario&feature=search_result#?t=W251bGwsMSwxLDEsImNvbS5zdXBlcm1hcmlvIl0.