Collaboration software was about helping teams of people, typically on projects or with a need to share information to get a job done, to set up 'collaboration spaces' or 'team rooms'. There was not a lot of process enforcement, because the workflow capabilities of the products were limited and the aim was to focus on ad-hoc collaboration of people, rather than strict process flows.
This lack of process management was probably a shortcoming, since companies grew able to share information online easily, but still struggled to put some structure around the work that was done. And maybe collaboration's demise was due to the name 'collaboration'. A guy I worked with at Vignette, Casey Conner wrote a book with Christine Lambden called the Consulting Stance. It contains many thoughts about how consultants communicate, and if I have remembered well, there is a story about how a consultant failed for a day to communicate with a team in Europe about the value of collaboration - a 'collaborator' still carries negative connotations for many Europeans brought up around the time of the World War II.
Even if collaboration software just died because its marketing showed limiting insight, and its technology missed the mark a little on what businesses really needed to improve the way they work. Social BPM is a land-grab by BPM vendors to help them reclaim some flexibility in their otherwise fixed, rigid product sets. Companies wanting to improve should also search for solutions offering other capabilities such as workflow management, and rapid process improvement when going out to look for solutions on Google. Social BPM has appeared on my website, but its not there to try and charge companies enterprise software prices for common 'social' software capabilities.