Jay-Z is will be releasing his mixtape in a few week. Personaly I couldn't "differentiate"(That word of the day calender is really kicking in, lol) between Jay-Z releasing an album or a mixtape. So I started surfing for some knowledge. I came across this MTV article that "sheds" some light. I'll post a some "portion" then "provide" a link to the rest of the article.

-- by Shaheem Reid, with additional reporting by Sway Calloway, Rahman Dukes, Darin Byrne, Heather Parry and Curtis Waller

When 50 Cent's LP, Get Rich or Die Tryin', dropped on February 6, it was something like the 20th release of his career, though the first official album you could find from the rapper on the shelves at your favorite record store.

50, the latest star to come out of Eminem and Dr. Dre's Shady/Aftermath camp, had already found great success in the music industry. But not that music industry. The other music industry, the one where labels don't exist and there are no highly paid Lizzie Grubmans to publicize your new release, where the CDs are sold by vendors hawking them off dirty blankets on city streets, and bootlegging is encouraged. Welcome to the world of mixtapes — artists as big as P. Diddy use mixtapes as radio for the streets, and new rappers will do anything they can to get on them if they want to make a name for themselves.

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MTV Article