The scariest button on your computer is "reply all."
We've all got the scar tissue to prove it. Tell me you don't hesitate before you click that button. The repercussions for you on either end of "reply all" are not pretty.
Problem is, we've outgrown email and now use it for way more the simple 1x1 messaging system it was meant for. We desperately need space to collaborate, not just message each other. Because there's no space, we end up ccing a bajillion people and then having endless threaded conversations. Most of these conversations consist of responses like, "no problem" or "thanks."
Email is convenient for recaps, updates or communicating with people outside of work, but it's horrible for quick and effective collaborating. There are a lot of reasons email isn't good for collaborating but let's pick one (you can add the others).
The one that I always think about is a story my college psychology teacher told. She said that when someone is laying on the ground in a small town and someone walks by they immediately stop to help them. In New York, however, everyone walks right over someone on the ground because they think that someone else will help.
The same thing happens with email. Someone else who received the email will help, won't they? Anyway, the last thing you want to do is to reply all.
In an open space, like Clearspace, no one is addressed as the recipient of a question or document. So, while even more people can access the information than anyone you would have added to an email, people don't feel as scared and are more likely to participate. They could be the only person walking by, right?