Minify your HTML by removing all the unnecessary characters.
Minify your JS by removing all the unnecessary characters.
Get the gravatar.com globally recognized avatar for any email.
Check if the URL is banned and marked as safe/unsafe by Google.
Extract email addresses from any kind of text content.
Make sure your passwords are good enough.
Find A, AAAA, CNAME, MX, NS, TXT, SOA DNS records of a host.
Get the web-host of a given website.