BCS has an interesting feature on presence technology:
"Being able to see individuals over the network provides organisations with the ability reach people almost anywhere when they are available, and importantly it gives the individual user the flexibility to control how they want to be reached. Communications, and by extension, the workforce, can stop being desktop centric, and start to incorporate the use of mobile internet devices and PDAs much more effectively.
For example third-party enterprises involved in a project could be given presence access to a particular folder of work for a specified length of time. This could help businesses to work more collaboratively and, importantly, to build stronger relationships, both of which ultimately can only help the bottom line. "