It seems that a developing trend in online services is the ability to store files online (or "in the cloud," as they say in the trade :) ). The first product that I was aware of offering this service is the Windows Live Sky Drive. Today, I learned that Adobe is offering a comparable service, Adobe Share.
The basic premise of these services is that they allow you to upload files to a server and permission them so that other authorized people can access them. The benefits of this model include increased collaboration and obviation of the need to send files as email attachments.
I think the idea of such a service is good. I like offering new ways to share information, but I wouldn't I would use such a service to store my only copy of anything or anything confidential - but, that goes without saying, really.
Anyway, if you are looking for ways to share files with other people and you are sick of the versioning hell it creates to mail document revisions back and forth, I would recommend checking these services out.