I recently seen stikkit and when I saw the demo it sounded very promising. It's basically a notes program, which I personally think is very useful to store information as little notes. The interface is really cool. They are monitoring the text continuously for particular text formats that are recognized as calendar, contacts, to-dos or bookmarks. It didn't work completely for me, but it looks like a nice little application interconnecting information.
In a more company oriented line, I tried Zimbra. It's basically an inbox application that has a server side and client side component. It has great linking capabilities between email, contacts, calendar, etc. It allows you to define your own links, such as when you have an eBay item number or an invoice number in an email you can define a link to your operational application automatically. This kind of application seems great to have workflow and regular email in one same inbox.
I'm glad to see more and more connectivity inside applications like these two.