Suppose you bookmark this URL now, and one morning you can't reach RootsWeb. Use this bookmark to go to the traceroute site. If you can't get to the traceroute site, then your site is probably disconnected from part or all of the Net.
If you can reach the traceroute site and it can't find rootsweb.com, then RootsWeb is probably disconnected from part or all of the Net.
And if you reach the traceroute site and it reaches RootsWeb, then there's a routing problem between you and RootsWeb.