Money flow, who gets the money and for what?

Millions of Linden Dollars change hands every month for the goods and services Residents create and provide. This unit-of-trade may then be bought and sold on LindeX (Second Life's official Linden Dollar exchange), or other unaffiliated third party sites for real currency.
a) money earned by Linden Lab

Premium accounts, additional basic accounts fees.

Additional fees are required for reactivation, cancellation of the account.

Land purchase and maintenance costs.

To get the picture the Islands are priced at US$1,675 for 65,536 square meters (about 16 acres). Monthly land fees for maintenance of the island are US$295. Additional fees are asked for the land resale after the account is cancelled.
b) land developers
When buying a land you can choose to develop it yourself or ask professional Land Developers to do it for you.
c) user-to-user money flow
Users providing services get their incomes from the customers (other users of Second Life)