Rasmus Lerdorf's article on the characteristics of PHP on the Oracle Technology Network:

"Popular opinion about PHP is polarized. Language purists tend not to like the somewhat haphazard implementation of many features and some of the inconsistencies that have emerged over the years. At the same time, pragmatic problem solvers tend to love how PHP seems to almost read your mind and present itself as the perfect Web problem solving tool."

"About the lack of enforced structure, all I can say is that I absolutely hate programming frameworks that lock me into a certain way of approaching a problem. That doesn't mean I don't believe in structure and frameworks, but I do believe in people having the power to come up with their own to match their environment. [...]

What it all boils down to is that PHP was never meant to win any beauty contests. It wasn't designed to introduce any new revolutionary programming paradigms. It was designed to solve a single problem: the Web problem. That problem can get quite ugly, and sometimes you need an ugly tool to solve your ugly problem. Although a pretty tool may, in fact, be able to solve the problem as well, chances are that an ugly PHP solution can be implemented much quicker and with many fewer resources. That generally sums up PHP's stubborn function-over-form approach throughout the years."

"The lack of a central control process is a feature and at the same time a source of great frustration for many. The shared-nothing architecture of PHP where each request is completely distinct and separate from any other request leads to infinite horizontal scalability in the language itself. PHP encourages you to push scalability issues to the layers that require it. If you need a shared datastore, use a database that supports replication and can scale to the levels you need. If you need to load balance requests or distribute certain requests to certain servers, use a front end load balancer that supports this. By avoiding a central controlling process, PHP avoids being the bottleneck in the system. This is the defining characteristic that separates PHP from what people commonly refer to as application servers."