The HOSTS file shouldn't slow anything down. If anything, it will completely block you out from a site...which is what it's suppose to do.

also, a site named www.upsellit.com should be banned from your hosts list if you do autosurfing, as it is the site I identified off of multiple (4) sites during autosurfing that gave the javascript popup/chat box trying to give a "free" vacation while jamming your autosurf session.

These modified hosts file (especially the one from MVPS - http://www.mvps.org/winhelp2002/hosts.htm) will always be growing as more of these garbage/nagging sites show up. I recommend just going to a dedicated source like MVPS and get the new hosts file whenever they release an updated one.

Remember, the hosts file can sometimes block out some site that you want access to. If you encounter these cases, just go to C:\Windows\system32\drivers\etc and open up the hosts file in Notepad. You can delete the line where the site is located. Save the file and you should be able to visit the site again after a minute or so...I just close my browser and open it back up.