keep track of historic events per unique visitor. like: - initial search phrase used to find you site - most recent newsletter / partner / campaign responded to - goal conversions - perhaps a few custom fields which an ebusiness can use to identify buyers while an informational website can use it to store the visitor's specific interest this kind of information can be very useful for, for instance, segmenting your audience, search phrase / key word performancetricky bit will probably be making sure that the correct record is mapped to the correct visitor
All this data is available in the piwik_log_visit (some help on the wiki)table already, so this could be as simple as reading the data and displaying it properly.
The hard bit would be to make it scalable: easy to do segmentation on a few hundreds visits, but how does it work on hundreds of thousands visits?
marked as duplicate of #44 as this plugin could be extended to provide this data