The following is a summary of the releases of Roll20 updates, along with a link to the forum post/full changelog for each.

June 25, 2013

• Usability improvements to the Character editor, tokens, macro quick bar, etc.
• Group rotation and scaling added
• WebRTC trial underway to test new video chat implementation

[1]

June 6, 2013

• Small update focused primarily on improving lost connection detection

[2]

June 4, 2013

• Modules (collections of maps, tokens, sounds, characters, and handouts which are pre-generated and made into a Roll20 Campaign) were introduced. One free and one paid module were available at launch.
• The Roll20 API was enabled on the Main Server for Mentor users.

[3]

May 14, 2013

• Card decks were improved, with additional options for how cards are played to the tabletop, new hand management display, and a discard pile.
• The API was further improved, including state object persistence between play sessions and the ability to create new objects

Full Changelog

April 30, 3013

• The Roll20 API was introduced
• The Roll20 Wiki was unveiled.
• New features for the Journal including tagging + searching journal entries, drag and drop re-reordering of attributes and abilities, players can edit Handouts, and more.
• Custom turn order entries
• Hide the right sidebar
• Macro and abilities editor made easier to use

Full Changelog