What can you expect from the mainnet? The mainnet is split into two parts. Firewalled Mainnet and Open Mainnet. Firewalled Mainnet (enclosed network) has limited functionality. There are no exchanges or other blockchains connected to the Firewalled Mainnet yet.
In this type or kind of Mainnet, ONLY P2P TRANSACTION IS ALLOWED. Example, if a Pioneer wants to buy a pair of shoes from other Pioneer, that is allowed. However, EXCHANGE OF PI TO FIAT OR OTHER CRYPTOCURRENCY IS PROHIBITED. There is a possibility of penalty when a Pioneer violates this provision. This Mainnet is similar to IAT (In-App Transfer). In-App Transfer was only available to few hundreds of Pioneers, it was implemented in 2020, its purpose is to test the P2P transfer. Today marks the launch of the Firewalled Mainnet, as well as the release of two new sections of the Pi white paper that explain how mining and supply work.
Open Mainnet, this is the fully functional Mainnet, no more barriers. It is now allowed to connect to exchanges and other blockchains. This will happen between the Pi Network Day (March 14, 2022) or Pi2 Day (June 28, 2022).