If you're trying to separate your online advertising from the herds of other ads out there, you might consider the approach to rich advertising outlined by Dorian Sweet in "The Rich Ad Addendum".  The post, which really is an addendum to a previous article by Sweet in 2005, talks about some of the aspects of a successful rich ad.

Sweet describes a rich advertisement as a three-act play:

1. ACT I:  Get the user interested
2. ACT II:  Get the user interacting and entertained
3. ACT III:  Give the user a reward for their engagement (a great newsletter, exclusive content, or a special deal)

He goes on to talk about ads that start out well, but fail to make their way through all three acts.  Ads that grab the user's attention, but then stop, are not only unsuccessful… they also down-right annoying.

Sweet continues to examine what's changed since his initial article almost 2 years ago.  For one, he says, video has become not only accepted, but also a medium that users respond to.  And with more bandwidth pipeage, you can do more with rich ads today than you could 2 years ago.  But, Sweet warns, that doesn't mean you should cram the kitchen sink into your ad just because you can.

Ultimately, he says, you've got to continue thinking about users.  They won't just accept any ol' form of advertising anymore.  According to Sweet, customers respond better to quality, humor, and "beautiful copy".  Experiment and test your rich advertising to see what customers respond to the best.

If something doesn't work, throw it out and start over.  What have you go to lose by getting rid of an under-performing advertisement anyway?