DNS = domain name servers.
When you type in an address the DNS handle the request for you. Unless you've changed anything you will be using your ISP's DNS, normally OpenDNS is faster but at the moment it's having problems for UK users so it's not worth trying, so I won't go into detail.
Pipex is my internet provider, so I have changed my DNS from OpenDNS back to Pipex's own.
This forum does appear to be running a little slow, so I don't think it's just you.