As our userbase grows we would like to reiterate a common mistake made while using the software: not knowing the difference between an alert and a filter. Here's a great FAQ we wrote on this topic: http://www.trade-ideas.com/FAQ.html#Q23
We often receive questions like, "How come I did not see an alert for such and such a stock?"
Most often the answer lies in the filters that are selected. For example if you wonder how come you didn't see BIDU or GOOG or something similar, first check the Window Specific Filters for your alert window (under Configure). Something as minor as a maximum spread filter of 15 cents can easily keep volatile stocks out of your alerts window. A good way to successfully test and configure an alert window for results is to use the History feature.
Good luck and good trading!