The Forbes article outlines some great moves by ownership to increase team value:
1) a seven year deal to play in the Garden for free
2) getting CSNNE to give up a 20% stake to the Celtics, as well as a boatload more money in local TV revenue
3) marketing like crazy to increase revenue
4) using sophisticated methods to maximize seat revenue
What's ironic about NBA finances, after a huge investment of over $350m and a decade of hard work to increase revenue, their $19m profit last year was (slightly) bettered by the salary made by Gilbert Arenas, who played 200 or so minutes. in 17 games.