Anyone who is into a particular artist will keep a look out for any new material they produce in anticipation of purchasing it, they have heard the artists previous efforts and are willing to get their new shit. These people are the first to buy the new stuff, then there are those are influenced to buy by a combination of word of mouth, airplay, billboards, publicity and other promotional activity. there are many reasons why an artist sells, Common has a dedicated fan base - but these real dedicated fans make up only a fraction of the total sales of his album, the rest bought the album because a friend reccomended it, they saw the video, heard Common on TV....the list goes on...we are in an age of promotion first, evaluation second...there are millions of people who simply buy because they are influenced by advertising, hard to bear but true...peace j-quest