Lots of times, class::dbi is used in web-based applications. (in fact, coupled with a templating system that allows you to pass objects, such as template::toolkit, class::dbi is very much your friend for these.)

one of the most irritating things about writing web-based applications is the monotony of writing much of the same stuff over and over again. and, where there's monotony there's a tendency to skip over stuff that is really important, but is a pain to write - like taint checking and sensible input validation. (especially as you can still show a 'working' application without it!). cgi::untaint can take care of a lot of that for us.

it so happens that cgi::untaint also plays well with class::dbi. all you need to do is to 'use class::dbi::fromcgi' in your class (or in your local class::dbi subclass that all your other classes inherit from. you do that, don't you?).