Your idea is along the same lines of .....
http://ideas.omniture.com/t5/Omniture-Idea-Exchange/Based-Alerts-for-relative-changes-in-b
ehavior/idc-p/363#M336
I set text search based alerts on an hourly basis, but if I set the
alert every hour, then I'll get an email every hour regardless of
whether the criteria was met. All I really want is to see the alert if
it comes back with something. We should have the option to check a box
that says "check here if you do not want to get an hourly report, if
there is No Data"
Another alert based feature would be the ability to set alerts that
allow you to just see positive, or negative percentage changes. You
might not care if it goes down, but only if it goes up. Also, along the
same lines with relative changes in behavior, this would solve the
problem that weekends cause for many marketers. If you could compare
Saturday to the previous Saturday, this would prevent useless alerts
because of natural swings in the data.
