Piano rock is a style in music which is based on piano or similar instruments (like keyboard and synthesizer). That is the main difference of this style from classic rock which is usually based on guitar (or several guitars). So, playing in that style leads a very important and active role. Through the time of development this style was not as popular as classic rock but piano rock compositions inspired many modern rock artists. So, even not being prevalent as classic rock style it was very influential.
Roots of piano rock style go back to 1950s - this style appeared with performances of piano rock pioneer of 1950s Jerry Lee Lewis. His manner to play the piano was new at the time but very interesting (so it attracted many people). Most of the Jerry Lee Lewis's techniques are still used in modern piano rock by different artists. Of course, modern piano rock differs from what it was back in 50s but still all these methods are attractive.
Although Ray Charles is usually thought of as jazz musician he actually was a piano rock pioneer. He brought "blues" sounds into piano rock. And his melodies also as performances of Jerry Lee Lewis inspired many modern artists - and not only rock artists but also pop, jazz and R-n-B artists. So, music of piano rock pioneers was really influential.
But modern piano rock is also very developed. It is still not as popular as classic rock but it has its admirers all over the world.
The most well-known names in modern piano rock are Elton John and Ben Folds. Of course, there are many other bands and solo artists like Tori Amos and Rufus Wainwright playing in piano rock style but these two are probably the closest followers of piano rock pioneers. They both try to play in a manner of Jerry Lee Lewis. And of course, they add new nuances to this style. For example, Elton John (along with another modern piano rock musician Billy Joel) managed to combine styles of Jerry Lee Lewis and R-n-B music of Ray Charles.
Benjamin Scott Folds was born in 1966 (September, 12). Today he is one of the world famous pianists, singers and songwriters but in fact his career started differently. The first instrument he was performing with was drums; he also was performing in band called "Majosha" as a bassist. But only in late 80s he became famous as a pianist of "Ben Folds Five" band. He also performs as solo artist. In fact, there is no strict definition of Ben Folds style in music but most people use terms "piano rock" or "indie" talking of him.
Sir Elton Hercules John is another great figure in modern piano rock. He is one of the greatest modern composers, singers and pianists. He probably was the dominant figure in development of piano rock in 70s. At that time guitar was still the main instrument and he helped to keep the "rock" style from becoming guitar only style. It is really hard to calculate all the possible music awards that Elton John has. For all his achievements in modern music of different styles in 1988 Queen Elizabeth II granted him the title "Sir". And in 2005, even a statue of Elton John was made for the museum of Madame Tussauds.