Q:

What is wrong with running unix processes with &?

I have seen tools to daemonize processes.
But I have seen that:
some_command &

Runs process in a daemonized way, is this way bad? how is this way called?
Update
My doubt is that I am calling that command inside an ssh session, will the process last after closing ssh session?

A:

That's not daemonized, that's simply running it as a background process.
A true dameon is a lot more involved; see e.g. http://en.wikipedia.org/wiki/Daemon_(computer_software)#Creation.

