If I were searching for an apartment, I would more than likely not use print ads. From the time someone calls in to have their ad printed in the next issue of the LA Times (or your local newspaper) to the morning you scour the Classifieds, a lot of things could have happened to change the situation. On the other hand, it's good online posting etiquette to take down a want ad once the vacancy has been filled, so if I see a listing that appeals to me, it will probably still be there when I call. I could also see whether the ad has been posted repeatedly or for an extended period of time (if no one else wants it, maybe there's good reason for me to reconsider...).
Besides, the internet has such pretty colors... :)