Insightful post - thanks. In 1999 I coined the phrase "Email is where knowledge goes to die." and I was hopeful that Xobni would force me to recant. It didn't. Even with Xobni, a great deal of knowledge nuggets burried in your email system remains unfindable.

I used Xobni for about a year while in beta and I enjoyed the ability to look at information from a people perspective - truly innovative and a refreshing perspective. However, the primary reason I started using it was to solve the personal search crisis.

While search in Outlook is a good start, it misses a bunch of stuff including Outlook PST files that are not loaded in Outlook. Some of us have PST archives dating back Internet eons - mine start in 1994 - I have 100% of everything sent and received since then. But I can't get Xobni to index them unless they are all open in Outlook - a physical impossibility. As such, Xobni falls down on this requirement, but so does every other unified email search solution (that I'm aware of).

Another failure of Xobni is that it has Outlook blinders on. To provide a comprehensive search and social framework for dealing with online activity and increase productivity, there are many data sources that should be considered. Xobni is biased toward Outlook (for obvious reasons) - it is a plugin and at the whim and [limited] perview of what Outlook has for data.

The light at the end of the tunnel may be Gist - I have high hopes for this startup which takes a little different approach to rescuing knowledge perhaps long after its death. ;-)