In traditional sense a play list is a collection of songs that are played in a certain order configured by the user (the winamp way).
When I initially created Goggles Music Manager I was opposed to having play lists. Basically I just wanted to play albums and didn't want to deal with first creating a play list of songs before I could listen to anything. I prefered the iTunes way of doing things, in which you select the artist and the album you want to listen to.
What I didn't realize until now is that a play list can basically function as a subset of your music grouped according to some crititeria. For example: James Bond Soundtracks, Christmas Songs, Star Trek Soundtracks etc.
So in the next major release of Goggles Music Manager you will have the ability to form play lists or subsets of your main music library. You will able to browse these playlists the same way you browse the main music library, but with the additional capability to queue songs as well ( the winamp way ).