Google wave is touted as the next big thing from Google assisting in real time collaboration. So if you thought why it is so necessary, here are some recent stats from a Forrester report (the study is close to a year old, but still relevant)
99% of knowledge based workers in USA and Europe collaborate with others at work
70% of American workers and 81% of European workers regularly collaborate with people outside their time zones and geographical locations.
Most Preferred Way, Given a Choice : Telephone, Face-to-Face
Most Preferred Way in actuality : Email
Use of Web 2.0 enterprise solutions : With the exception of Instant messaging, there is very low adoption rate for blogs, wikis, etc.
Given the fact that the most preferred real time collaboration is not in fact so real-time, there is definitely a scope for Google wave.