There was a time when brands turned their noses up at banner advertising.

Poor click-through rates led marketers to believe that consumers simply found banner ads annoying so they switched much of their online budgets to search engine marketing instead.

But have things changed? Is banner advertising now an effective way to reach consumers? Or do banners still annoy people?

Most of us try and ignore the banners on the websites we choose to visit, but do we subconsciously take in their marketing messages?

Many brands now seem to think so and think there is brand building mileage in these now ubiquitous little animations.

Or maybe advertisers have woken up to the fact that the success of a banner ad campaign cannot just be judged on click-thorough rates but on increased brand awareness.

Ironically it is the search engine giants that seem to be backing this resurgence. First Google, then MSN and now Yahoo! have been buying the networks that serve up the ads like they where going out of fashion.

Google started the trend when it bought DoubleClick earlier this year. Most of us thought that, having mopped up most of the worlds search advertising budgets, they were expanding into banner advertising because there was simply nowhere else for them to expand their revenues.

Then Microsoft bought online ad and marketing specialist Aquantive for $6 billion. AOL bought behavioural ad company Tacoda for an undisclosed sum this summer. And WPP bought Real Media for $649 million in July.

Finally, last week saw Yahoo! purchase performance-based behavioural targeting network BlueLithium for $300 million.

This all begs the question, are there any independent ad serving networks left to buy, and if so, why don't I buy shares in one?

BlueLithium records surfers' activity to determine which ads to show them next, then only charge advertisers if the ad leads to a sale.

But I think you'll agree, if you're after a few million quid for your company, 'performance-based behavioural targeting' sounds much better!

Is this just Yahoo! covering its position as the world's second largest online media company in case Google have got it right and brands are about to switch from search to display advertising, or indeed their outdoor display advertising to online?

Or is it a fact that increasingly online savvy consumers now accept banner advertising as necessary evil that pays for the free content we enjoy?

It could of course be that banner ad designers have just got better and engage us more than annoy us with distracting gimmicks. Or perhaps they're getting the balance of the two right.

There was a time when the web was regarded as just a response medium for driving registrations, special promotions, free trials and discounts, not a mass medium for creating awareness and building brands.

Google and Yahoo! obviously think that this opinion amongst brand marketers has changed.

Chris is head of digital at WAA ( Email