Sure. But none of them support the applications these developers have already built.

It's one thing for Apple to set guidelines on what it's going to allow in the store. It's another thing entirely for it to not set guidelines, but instead force developers to figure out for themselves what is allowed based on which apps have already been accepted. Now Apple is changing the rules on the fly, so even apps that historically have been acceptable may not be allowed in.

If Apple wanted to keep these promotional spammy apps out, it should have started blocking them from the start, before people started building businesses around them.

Now I'm wondering how long it will be before Apple starts removing the many thousands of book applications on the App Store, now that it has its own official Books app.