don't replace your current one, just append everything after the [quote]#start of lines added by WinHelp2002/quote] part to the end of your current /etc/hosts...
you can also use another hosts file from somewhere else instead.. there's plenty of them floating all over the web...
what this does is it will prevent your machine from openning connections to the listed web addresses, which are mostly ad servers and spyware sites, etc... so when you go into a page with a bunch of ads in it, the ads won't get downloaded by your browser... it helps save bandwidth and thus speeds things up somewhat... on sites with lots of ads the speed boost can be quite dramatic...
check this out:
http://accs-net.com/hosts/hostsforlinux.html
good luck...