Amazon MP3, Facebook apps are tied to some services that requires user accounts.

One pre-installed app on iOS that fit the category is YouTube App.

So now that there are installable apps, they can be removed, right? No they can't.

Yes, this could (and should) be fixed. And someday, perhaps, it will be. For now, it's just not a serious problem, outside of Hacker News.

Having three different IM clients on a phone pre-installed and unremovable? Yeah, that's the kind of shit Apple doesn't do.

Because Apple wants you to use SMS instead of IM, making the carriers a boatload of money for no reason.

That is exactly the kind of shit Apple does.

I bought my first mobile over twelve years ago because of SMS, not voice, as it replaced the pagers that me and my friends had.

Apple's SMS implementation/interface is terrible. Group Messaging is just broken.

I wouldn't use Amazon mp3 nor facebook, so, meh.

Notes is okay - but I prefer simplenote.

I also don't use the contacts app (you can get at contacts through the Phone icon) but I understand that people might want to use it.