A usage pattern I have seen so far
It starts of as a trickle. One person creates a work space in a collaboration tool to share a thought, notes or a document as part of a particular assignment. She then invites two of her colleagues to view and comment on the document and notes. One of the team members, who is not really interested in collaborating online accepts the invitation and joins the work space just because the first person invited her. She does this because of peer pressure. She does not want to be seen as not participating.
The third person works from a location away from the main office. So this person find the collaboration space useful to keep everyone informed about what she is doing. So she post her work there. She then invites her manager to the space so that her manager can see her work in real time. The manager monitors the space to see what is going on.
Meanwhile a junior member joins the conversation and comments on the content posted by a senior member because the work space flattens hierarchy a bit. Any one can theoretically talk to anyone without others interfering in real time. The senior member responds and the conversation gets interesting. Other senior team members join just to keep tabs on the conversation.
Enabling collaboration in a company
Based on such behavior I believe that in a 10,000 person company all it will take to kick-start usage is for 100 people to start using a collaboration tool for their day to day work. In a company with 50,000 people if 500 people are identified, selected, trained and motivated via incentives to use the new tools for their day to day work, that should get the company going. This is doable.
How enterprise software can help
Enterprise software can improve the adoption of collaboration tools by surfacing content from business applications that people use everyday in collaboration tools. For example, performance management tools can surface performance goals; sales automation software can surface sales opportunities; procurement tools can surface procurement projects in collaboration tools and make it easy for employees to consume, discuss, execute and contribute.
Providers who build both business software and collaborations tools have an opportunity to build bridges between collaboration tools and business context. I hope they take advantage of this wonderful opportunity in front of them.