"Straight up" whack

I am easily confused by many things... not the least of which being the music industry. Maybe someone out there can explain this one. Here is the quote (emphasis mine) from the article in question:

"...Paula Abdul has apparently decided to revisit her days as a recording artist by putting out a greatest hits album, titled Greatest Hits: Straight Up! The album, slated to hit stores on May 8, will include all six of her number one singles and eight top 10 hits. It's the first release from Abdul since her last greatest hits album, 2000's Paula Abdul: Greatest Hits."

So how can one have a greatest hits album, publish no other music, and then have a new greatest hits album 7 years later?

I think that when I get my first record deal, I jump straight to the greatest hits album right off the bat.