Back in the day, online display advertisements used to be all the rage. And then Google AdWords came along and blew the lid off of online advertising with its simple text-based ads and its cost-per-click model. Advertisers were able to quickly create a terse, compelling chunk of text. Users were clicking. Revenues were rolling. All was right with the world.

But recently, something changed. Now, we’re suddenly seeing a renaissance for the display ad. Today, Google is getting into the mix with the release of do-it-yourself display ads.

So how difficult is it to build a display ad? In typical Google fashion, they’ve done their best to make it push-button simple. Some copy here, a graphic or two, and a few clicks and you too will be on the road toward becoming the creative director of your own online advertising shop:

Once the creative is complete and you’ve chosen your preferred formats, you will be dropped into the now intimately familiar AdWords purchasing and placement interface.

As with most of Google’s offerings, the new service is quick, easy, and relatively painless. What’s more, it offers a whole new realm of expression that will help advertisers differentiate their offerings from their competitors.

I’m sure that many online advertisers will love the new creative freedom that these quickly built animated ads provide. We’re likely to see quick uptake.

But will this new creative freedom for advertisers translate into more clicks?

This week, we saw MySpace launch MySpace MyAds, a service that allows any user to quickly build and deploy display ads targeted at MySpace users. Seeing Google quickly following the MySpace lead with a similar service begins to feel like a trend.

Part of the reason for Google’s success with text-based ads had to do with the fact that users had grown weary of display ads. In fact, they had begun to ignore them. People just weren’t clicking.

Now, one has to wonder if – with the recent resurgence we’re seeing in display ads – that same fate has begun to plague the text-ad format.

When Google unveiled simple – and more importantly, relevant – text ads in the context of search, it seemed to be the silver bullet for online advertising. Will a return to the display-ad format prove to be an equally compelling shot in the arm? That remains to be seen.

Some marketing analysts, like Marketing Sherpa, claim that display ads are “back with a vengeance.” Others, like Starcom MediaVest Group, maintain that display advertising metrics are inconclusive because less than 10% of the users “account for 50% of all display ad clicks.”

Whatever the opinion, one thing is sure: For companies that live and breathe on advertising click-through rates – and that support an even larger ecosystem of companies relying on ad-based revenue – cracking the code of “the modern Web user’s advertising preferences” will be the key to survival.

If anyone has the potential to crack that code, it’s Google.