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.
Google has a URL shortener called goo.gl. Originally Google's URL shortener was used to pass links internally to other Google sites, but the service was expanded to include external links and opened to public use.