Minify your HTML by removing all the unnecessary characters.
Minify your CSS by removing all the unnecessary characters.
Get approximate IP details.
Find A, AAAA, CNAME, MX, NS, TXT, SOA DNS records of a host.
Get all possible details about an SSL certificate.
Make sure your passwords are good enough.
Get the web-host of a given website.
Get & verify the meta tags of any website.