Is Future of Email Twitter, IM, or Something Else?

Some think the future of email is Twitter, while others think it is instant messaging. Some might argue the future of email, if not in total message volume, is some upgraded version of today's product. 

For the moment, though channels are proliferating, email is likely to remain in use because none of the other newer channels have some of the advantages of today's email. But email increasingly is one channel of many people use for communicating and collaborating.