As part of our research into customer behaviour and requests, we do keyword searches in activities (call/email). It is easy to pull a report showing a trend over time for a single keyword/phrase by filtering by say email that contains any of "Support". However, if I wanted to pull a report on more than one, say email that contains any of "Support", "Complaint", "New Customer", they are added together in a single line, which is of no use. The only way to differentiate these is to create a separate report for each keyword/phrase, which will make dashboards unneccessarily large and unwieldy. If you could split the line on a single graph to show the number of emails with each keyword/phrase, it will reduce dashboard sizes and increase their usability.
Additionally, on the dashboard if you can select/deselect these words to update the graph like you can do with other similar types of graphs (e.g. number of tickets by ticket owner), then even better!
