Big fan of Piwik and especially the 'Visitor Log’ feature - the ‘blow by blow’ account of visitors is very useful to us, particularly when we can see traffic from clients or customers and can call them when they are thinking of us!
What would be fantastic would be if we could get an instant notification (probably via email) when a visitor that matches a particular segment arrives on our website. This could be applied to goals and probably in other interesting ways too, as the user desires.
For example, alerts could be received like: “visitor 184.108.40.206 from city, country just completed goal: checkout”, or “visitor from customer provider “importantcustomer” is browsing site now!”
Notifications like the examples above could be built by the user using some sort of template/tags, for example $visitorIP$, $goal$, $visitorcity$, $providername$ etc.