Virtual hosting is when sites do not resolve to specific IP addresses. It's the most common type of hosting.
What the HOSTS file does is this:
It's a list of domains and IP addresses. So when you type in the domain and if the domain is in your HOSTS list you don't need to have a DNS server lookup the domain's IP.
Thing is, IPs change all the time and the speed increase for doing this is negligible at best. So for this purpose there is no point in altering your HOST file.
Now there is another use for this file, you can use it to block certain sites. For e.g. if you want to block an ad serving site you can enter their domain and set it to resolve to local host (your own computer). This way the site is inaccessible and you can use this to block banners etc.
Thing is, you don't need any extra software to do this. All you need is a text editor like notepad.
Just add the domain you want to block and set teh IP to 127.0.0.1 (localhost, your own box).
I used to use this simple trick for all kinds of things. You can redirect sites to anywhere else you want for example. I played a joke on a friend and did this to all his favorite sites (redirected to a server that showed a page saying that the site closed). Then I redirected CNN to a server I controlled and I updated "news" about how the whole internet was closing. 'Twas verra funny.
Anywho, you can do the Hosts trick yourself. Just open the HOST file with notepad and block/alter what you want.
To find the HOSTS file:
Windows 95/98/Me c:\windows\hosts
Windows NT/2000/XP Pro c:\winnt\system32\drivers\etc\hosts
Windows XP Home c:\windows\system32\drivers\etc\hosts
The format for additions hsould be:
IP ---- DOMAIN (see below)
127.0.0.1 cnn.com
That would make CNN inaccessible.
You can download premade HOST files with hundreds of advertisers already listed. Here is one example:
http://www.accs-net.com/hosts/Downloads/Hosts.zip
If you use XP you have a built-in firewall already.
As to whois you need no program to do this. You can do it online. I'll throw up a whois tool here on A2K soon.
From windows you can do netweork type stuff through DOS.
tracert is teh command for a trace route on a domain.
use it like this: tracert able2know.com and it will tell you the IP and show you the hops.
As to popup stopper that depends on the browser. Heck as a webmaster I'd love for everyone to use the same browser...
See, you touched on the best and worst element of computers. The diversity of applications is both a boon and a bane.