Routers that you can connect USB STICK RAM or USB HDD what differ from Home Servers?

 

I'm assuming you mean you can attach USB memory (hard disk, flash etc) and use it to share the contents across your network? It's basically just a NAS (Network Attached Storage) device. Home Servers, whilst can act as NAS, can also perform other functions as well (web hosting, hosting apps and games, remote access etc). However, looking at it from purely a storage point of view there isn't really much difference. The router having the NAS capability is because it's for people who might not know what they're doing well enough to set up shares on a PC somewhere on the network.

 

There are some routers (you might be talking about one of them) that run Linux and can be set up for simple tasks. Someone I know used one for ebay sniping. Or it could host a small web site.

 

A lot of commercial routers & ADSL Modem/Router combos can be re-flashed with OpenWRT, which is a free linux distro specifically written for these embedded units.

It's completely configurable and open source.

It can add a lot of flexibility to what's otherwise very powerful but restricted hardware.

http://openwrt.org/