Nothing stops you doing this - with private address ranges, such as the 192.168.0.0/16 netblock and the 10.0.0.0/8 netblock. Technically you could use non private address space - especially behind an address translating firewall - but it's rude and may become a massive nuisance.
18.104.22.168/24 is a common address range to use. But that's all. People commonly use /24 address blocks, because it neatly maps to the IP address range octets. A netmask is a bit mask that says the first (24 in this case) bits are 'network' and the remainder are 'local subnet'.
That basically means 192.168.0.0/24 is 192.168.0.1 - 192.168.0.255. Another common convention is to adopt '.1' as the gateway, and '.255' as the broadcast.
Drop your netmask to 23 bits though, and you double the size of your subnet - 192.168.0.1 - 192.168.1.255. Each bit doubles the size. So whilst a /24 contains 256 addresses (8 'bits worth') - a /16 leaves 16 bits for host - 65,535 addresses.
The same is true of /16 and /8 - they map nicely to the octets of the dotted quad IP format. They are known as class A, class B and class C address ranges and once upon a time, when the internet was a much smaller place, that's all there was. Which is why you'll see a lot of (established) organisations have a /16 or class B, despite - probably - not using most of it on the public Internet.