Semantic Web has published a very interesting and detailed blog post on disruptive innovation in Finance listing the main activities of banks (by source of revenue) and the players that may challenge the incumbents.
Here is a spreadsheet summarizing the bank’s activities listed as well as the disruptive innovations and key players.
Link to the companies listed:
I would personally add a fourth category: Wealth Management. I think players such as Mint and Simplifi are opening a new market for wealth management, making it affordable/free for people to have a comprehensive view of their wealth and make informed investment decisions.