Piano Tabs have often confused me. Not because of what they are but because of how they managed to adopt the term "piano tabs". The guitar world has long been familiar with the phrases "guitar tabs" which refers to a notation system used for guitar music. It is the dawn of the internet which created an explosion in the availability and creation of such guitar tabs on a large scale. Pretty much every song ever written will have a guitar tab created for it.
Before long, pianists wanted a slice of the action and so piano music was also made available online. However, the phrase "piano music" is an already established phrases referring to published books contaning piano music and so for clarity's sake, online piano music became known as piano tabs.
Unlike with guitar tabs, there is no set format for piano tabs. It can simply be a list of piano chords placed above the lyrics of a song. Or it can be a midi file that has been created and upload which then allows it to be played back on any computer or printed out as a score using any basic midi file reading software such as Final or Sibelius. The other form is .pdf which offers more control over the layout of the music and generally a more attractive solution as it exists outside of any particular website and is not trapped within a website template. It is a self-contained file that can be downloaded and printed.