Are you an application developer? Do not do write applications that steal focus (i.e. if your email client pops up without you attempting to open the program). That was standard in 1998, but not in 2008. Like viral ads, applications that steal focus have no place in today’s world: they pollute the landscape and disrupt workflows.
And while I’m on the subject of poorly-designed applications, if you have an input field on the GUI, please make the field active from the time the GUI loads.