"Gather publicly available email-ids from search engines."
Metasploit is a framework of exploits, shellcodes, fuzzing tools, payloads,encoders etc. More over we can regard it as a collection of exploitation tools bundled into a single framework. It is avaliable in all major Linux, Windows, OS X platforms. It’s main objective is to test your/company’s/organization’s defences by attacking them. Something like “Offense for Defense”. This is actually where a penetration tester/Security Analyst begins attacking the victim after a huge recon. Metasploit has a wide range of tools & utilities to perform attacks agianst all operating systems including Android & iOS.