Quote Originally Posted by rugerpc View Post
The third note is an E - a very specific E - the E just above middle C on the piano. On a guitar in standard tuning, that E can be sounded by playing the 4th string at the second fret as shown in the tab.

Actually, the information given on the linked page is wrong. Middle C on a piano has a frequency of approximately 262 Hertz. Low E on a guitar has a frequency of approximately 82 Hertz. The E note one octave above it that resides on the second fret of the D string is approximately 163 Hertz. Middle C on a guitar actually resides on the 20th fret of the low E string, 15th fret of the A string, 10th fret of the D string, 5th fret of the G string, and the 1st fret of the B string. 

 The E on the first line of standard notation is actually the same frequency as the open high E string.

One can now clearly see why tablature is the preferred notation for guitar. We like to think of tab as being this hip thing that we developed for guitar. However, its use dates back to the Middle Ages. As Mikegarveyblues mentioned, one of tab's biggest weaknesses is that it does not encode timing.