Density is defined as how thick or thin you want your hair to be. The standard and most popular choice is 130% which is Medium Density. You can see examples of the density - Click Here.
Google's Gmail Web-based email service runs on the Internet Message Access Protocol system, but it also offers Post Office Protocol mail server access.
Understanding Email Protocols (POP, Imap, MAPI, EAS, Exchange) The email protocol is the process by which an email desktop/mobile client accesses the information (From and To) contained in an email account (your email address).