From the FFP website:
The IFOS - Advanced Abilities Supplement is a Web-exclusive for Invasion From Outer Space and features 4 new game cards for the Martian and Hero Decks and 10 new Advanced Ability cards (8 Hero and 2 Martian) as well as the new rules for using them. All pieces are printed on the same high-quality card stock as the boardgame. The cards are exclusive to this supplement and will not be available anywhere else.
The new Advanced Abilities cards can be added to any existing Scenario as a way for both the Heroes and the Martians to gain experience during games unlocking powerful new abilities. There is a unique Advanced Ability for each Hero character, allowing each to level-up and use a super-powered version of his or her Talent (requiring the use of a full 3 Power Tokens), as well as global abilities that the Martians can get.