I believe that collaboration will be a foundation of almost all software in the near future.

I've used Google Docs, particularly Google Spreadsheets, in a collaborative manner as part a puzzle hunt competition. We'd have anywhere from 2 to 15 people working on a puzzle at any given time, and everyone is making updates to the spreadsheet simultaneously - entering answers to clues, arranging the clues, creating new columns for listing interesting aspects of the answers, and so on. After an experience like this, it can be almost painful to head back to the office and work on single-user document tools, like desktop word processing tools, when my team is all taking notes at the same event. Maybe I should get the team to use Google Docs more frequently.

I believe that collaboration is powerful and useful; once the genie of collaboration is let out of the bottle of our collective software experience, it will be impossible to push back in. There are many software applications that will benefit from collaboration.. I think that, for most types of software, the ability to support collaboration will be a critical piece of a software's architecture.