What's your opinion about multi-user PCB layout?

Hi Everyone,
There's been a few ECAD packages over the years attempt to make electronics and PCB layout a 'team sport'. First there was a really expensive tool as I understand from Mentor Graphics, then Altium Designer had an SVN based compare and merge feature (not real-time editing), then there was Upverter, and just this month it released a real-time multi-user pcb editing mode.
To be completely transparent, I oversaw the product management, but I have little idea of a need for PCB editing 'team sports'. I can see some really good uses in education though.
But, when I personally think about why I design and make electronics and why I like to have it on a website, it's because I'm wanting to show others what I know about electronics, or just because I like making stuff and get a sense of accomplishment when I get something working for the first time. 
I've personally never worked on any board that was so complex and under such time pressure that I needed to get others to help me route it. 
But, there must be some use-case for this, because us EDA vendors keep talking about making tools like this. 
I'm interested to hear candidly from others in the forum what you think of this notion and under what circumstances you might consider "collaborating" on a PCB layout or schematic. 
This is not a trick question, I am just being honest about my own thinking and I'm open to be influenced by what others might have to say on this topic.