Take an IP and try to look for the domain/host associated with it.
Find A, AAAA, CNAME, MX, NS, TXT, SOA DNS records of a host.
Get approximate IP details.
Get all possible details about an SSL certificate.
Get all possible details about a domain name.
Get the gravatar.com globally recognized avatar for any email.
Make sure your passwords are good enough.
Get details of any file type, such as the mime type or last edit date.
Check for 301 & 302 redirects of a specific URL. It will check for up to 10 redirects.
Use the Google translator API to generate text to speech audio.
Extract email addresses from any kind of text content.