DNS Check - See DNS details and status
Traceroute - Follow request to my server and show how each hop is responding
Webserver response check - Is my website responding correctly
Mail server response check - Is my mailserver responding correctly
WhoIs Info - Registrar details

Search engine position for keywords :

IP Neighborhood - Find who is hosted on my server
Html check - Find html errors on my page
External links - Find all external links on my page
Internal links - Find all internal links on my page
E-mail addresses - Find all e-mail addresses on my page