The Content Management Revolution
I'll start with a definition:
Content Management System (CMS): a tool or set of tools designed to simplify website maintenance and allow non-technical users to add, change, and remove website content (text, images, pages, articles, calendar events, etc.) as needed. Most content management systems also reduce or eliminate the need for custom code to accomplish many common tasks.
When I started doing web development way back in the 20th century, content management systems were still fairly uncommon. Oh, there were a few commercial and free systems available, but they were rudimentary and either a) too inflexible to be easily adapted to specific needs, or b) so simplistic as to be almost pointless. The developers behind many of the larger websites found it easier to create their own proprietary systems to manage content and work-flow. The ability to rapidly reinvent the wheel was almost a prerequisite to successful large-scale web development.
The creators of smaller websites usually didn't bother with all that - why spend unnecessary hours or days trying to integrate an awkward CMS into a website when a well-crafted system of common "include files" could be set up in a few minutes? Of course, this meant that clients had to keep going back to their developers for even simple content changes to the website, but it drastically reduced the up-front costs.
Fast-forward to the 21st century: CMSs - and their close cousins, blogging software and social networking frameworks - are becoming ubiquitous. Most clients want at least a blog, and from there it's not a big stretch to expect control over other content as well. In fact, WordPress (the most popular blogging software) has had so many features added in recent years that it's now considered a full-fledged CMS. WordPress and other free, open-source packages (including Drupal, Joomla!, DotNetNuke, Elgg and others) are all designed to support additional plug-ins, whether free or commercial.
Chances are, the additional functionality needed for a website is already built and ready to use. Social networking, calendars, advertising, search engine optimization, e-commerce capabilities, and other features that previously seemed out of reach for many small business can now be added to a website in a matter of minutes or hours, rather than days or weeks. If custom work is still needed, the modular plug-in design simplifies the process.
Powerful, flexible, open-source software, combined with strong community support for added functionality, now means that advanced website features are within the reach of smaller websites and businesses. A well-organized, attractive, and unique website may still require a designer/developer to set up, but the client will receive much more value for their money.
Of course, technology is never flawless - and major website changes or problems may still require the help of the developer (or at least a technically-savvy owner, employee, or relative) - but the CMS has changed what it means to be a website owner.
Thanks to the CMS revolution, the stale, "electronic flyer" website of the past has been transformed into an opportunity to interact more frequently and directly with customers.