However, they make sense in some special cases.

1) It’s a distinctive feature of popular blogs to use 125×125px banner ads on the sidebar. A cunning blogger could “fool” her readers to think her blog is popular by using banners like these.

2) For marketing purposes, banner ads work better if they are customized for the website they appear on, perhaps using the name of that website or its owner.

3) Affiliate banners might work ok if they are seasonally targeted on a relevant site. For instance, holiday trip ads on a travel site at the time when many readers are making reservations.

In my opinion, the biggest problem with banners is poor execution: flash, animation, games, sound, non-customization, promise of prizes and other cheap click-through improvement tricks your typical advertising agency comes up with.

These annoyances make me stick to my AdBlock Plus.