There are so many calendar and organizational apps out there that the market for them has become more than a little saturated.
DateLine attempts to distinguish itself from the bunch by displaying a linear calendar on your desktop in a solid color or transparent line. This means that along your desktop, you have a piano keyboard-style layout of days of the month which you can double click on and then edit directly in iCal.
You can customize the background and text colors of the days, or simply turn them transparent to make them a little more discreet. I would recommend this because otherwise, it does tend to blight your desktop a little.
Overall though, there isn't much point to dateline. There are a host of applications for making iCal more easily accessible and the best solution of all, of course, is to have iCal open all the time. Dateline doesn't even highlight important daily events either which means it's only useful as a tool to access iCal and not to see what's coming up.
If for some reason you don't like having iCal open all the time or have your dock hidden, you may find some use for Dateline, although it's hardly a revolutionary app.
