Ajax in many ways is the basis for Web 2.0. The funny thing is that Ajax has been around long before the word web 2.0 was coined. Microsoft developed a Javascript function for Internet Explore 5 called XmlHttpRequest. This is the essence of Ajax. One single function which seems to have caused an overnight explosion of rich web-based applications.
Web 2.0 is based on this because Web 2.0 is highly interactive - similar to what you would find in a desktop application. Web 2.0 is about the rich user experience. No slow page loads or postbacks. Almost instant data and responses because most of the processing is performed on the client machine as opposed to the server (where most processing took place 5 years ago).
Google maps and Microsoft's LiveSearch both use a great deal of Ajax and web 2.0 methodologies. Another site with Ajax examples (the first one that showed up in search results) is http://www.ajaxdaddy.com/.
Marketpath CMS uses Ajax throughout the entire application on every page and every dialog. We could probably stretch all of our Ajax code from coast to coast in 12pt font.
Developing web-based applications with Ajax and web 2.0 methodologies is no longer cutting edge. It is a requirement for intutive, easy-to-use, and responsive user interaction.
Have you ever seen a faux balcony on a house? Or perhaps some other fake feature that had no functional use whatsoever? This really bugs me. Being a programmer, I am all about functionality. Luckily, our product interface isn't developed by me. If it was, it would likely resemble an emacs editor.

This picture causes strife in my life because I would insist on putting in real doors, not the appearance of doors. I like real. I like functional.
This goes for websites as well. I often come across sites that have a list of services or products that don't link to further information. I also see sites that have images that look like buttons but aren't linked to more information. And of course, the worst is when sites have broken forms, broken links, or broken images.
Now, I understand broken elements aren't planned like the ugly faux door above, but they are a product of the tools used, the individuals level of training using them, and the organizations commitment to the website. These small faux issues cause immediate headaches and frustration with visitors and will likely turn them away.
So be sure to check your website for broken elements and don't try to trick your visitors with the appearance of something that should truly be functional. Your website is not a Hollywood set. It is a direct extension of your voice and your message to potentital and existing customers.
And just for the record, my #1 pet peeve is double doors where one door seems to always be locked. Some even have a sign that says "Please use other door". Can't the people who unlock the doors turn the little key for the second door too? I don't get it.... but of course, I don't unlock doors for a living.
Probably not. So why would do so many marketers and business owners let their website visitors enjoy stale page content? Visitors come for a reason. They're evaluating whether or not there is something they want. They arrive with questions or curiousity. How well are their questions or curiosities answered?
If you look at a stale piece of bread from far off it is likely to appear normal. But if you inspect it closely, or worse take a bite, you will certainly notice it is stale.
Website content is no different. Visitors may, at first glance, think the content is fresh and updated, but with a closer look they will quickly get a sense that it is stagnant. Everything from the design of the site to the copy contained within, a website needs to convey relevant, convincing, and updated information.
With stale bread you can always cut it up and make crostini. But slicing stale website pages into little toasts isn't exactly an option.