Starcraft II is going free-to-play. In the following trailer Kevin Johnson, Blizzard's community manager, revealed that all of the games in the arcade and custom games section of Starcraft II are now completely free in the new Starter Edition. That means every custom map is now free instead of the rotation of maps that was previously available in the demo.
Modders can share their creations made using Blizzard's tools with the Battle.net community, and are being encouraged to do so (remember, a little known game called Defense of the Ancients was made using modding tools on Warcraft III). Scroll down for a second trailer which details more changes coming to Starcraft II in Patch 2.1.