All musical notation is a kind of compression, which is to say a compromise between ease of transmission and depth of reception.
The notes on a score tell you a lot about a song, but not everything. The same goes for guitar tabs, which tell you where to put your fingers, not what the notes are.
So, if you want to learn a song, it’s best to hear someone playing it decompressed, while using the notation as an aide-mémoire.
This isn’t an easy thing to do, especially in the repetitive way that’s necessary to learn a song.
Or it wasn’t until Adrian Holovaty and PJ Macklin created Soundslice, a beautiful HTML5 app that syncs professional studio recordings with sheet music and guitar tablature. Soundslice debuted in late 2012, but they released a new version of the software for sheet music yesterday, and it’s wonderful.