"Dead" domain name extensions list

Hello Pros.,
I frequently see in your comments here: "this extension is dead".
Usually it goes after questions about exact match domain names, from unexperienced domainers.
So, let's make a list of these "deads", to aware the newbies not to invest in domain names who look pretty, but nobody is ready to give a penny for them. Please, copy/paste and add your thoughts in the list I starting here:
So:
1.mobi
2.
3.
4.
5.