When Google firstly presented it's Google Wave, everybody though it was going to be a web client to integrate email, Twitter, RSS and basically... everything. If you are using Google Wave, you found out on your own that Google Wave is not for that.
But Mozilla created a client which is what many people though Google Wave was. It's called Raindrop, it's still pre-alpha and this guide will tell you how to install it in Ubuntu Karmic Koala 9.10. Why only for Ubuntu Karmic? Because probably some packages are too old to run Mozilla Raindrop and also, since I use Ubuntu Karmic, I cannot test it in older Ubuntu versions.
Raindrop is a Web service designed to collate, filter, and present content from disparate messaging services. It currently comes with support for Twitter, GMail, IMAP e-mail, RSS and Skype. One of the key goals is to use smarter filtering methodology to increase the visibility of important messages and reduce the amount of noise that tends to bog down Internet communication. Raindrop is built with a strong emphasis on extensibility, making it trivially easy to customize and enhance with new capabilities.