It's a good question. Off the top of my head:

- The transition from tree hierarchies designed for the industrial age command-and-control delivery of product, to graph hierarchies that deliver constant innovation.

- Remote working as a mechanism to attract and maintain more talent (and enabled by the internet)

- The drive to reduce fixed costs within businesses by outsourcing and collaborating with other businesses

- Driving down costs/improving producivity
- Offering conveniene and flexibilty to collaborators
- Accessing talent in disperate locations and time zones, enabled by technology/tools

Some of the the major trends driving collaboration are
- The need to engage better with colleagues and external stakeholders
- The need to have a consistent, centralized and browser-accessible repository of content that updates in a timely manner
- The need to be able to quickly locate relevant content and subject matter experts towards realizing a more productive workday
- To effectuate this knowledge sharing via an affordable, easy-to-learn and lightweight platform
- And to do all these through an enjoyable intuitive Web 2,0 style interface with tags, forums, page rating etc, etc

CIOs are emphasizing collaboration as a way to increase productivity and drive down costs. A simple IM on everyone's desktop in an organization can produce tremendous benefits. To be effective, tools must be simple and inexpensive to use.