There once was a time when the usable maturity of a platform could be measured by the gross cubic-feet dedicated to it at the local book store: More shelf space generally correlated with a more usably mature platform. A platform where development was often much easier.

Rather development was much more empowered, as it generally indicated that there were enough supports that you weren't sidetracked fighting the basics or reinventing the wheel, but instead were standing on the shoulders of greatness, pushing new boundaries of computer science.

Or at least implementing basic business requirements with a good probability that your needs can be fully accommodated in a relatively painless manner.

Applying the bookshelf metric, one would have observed that cobol probably wasn't a great development platform for most projects (outside of archaic insurance systems), despite its chronological maturity, whereas there was tremendous support for the C++/Windows platform.

As time went on, Java took the bookshelf lead, then saw its share pecked away at by the various web development platforms and the onslaught of Linux/UNIX.

The bookshelf metric really doesn't hold significance any more. Nowadays the dead-tree programming language industry caters more to the technological tourist than the serious developer (or the programmer desperately trying to earn team cred by stocking their bookshelves with various never-opened tomes). The last time I seriously used a programming-language specific book as a development aid was the 30lbs of Windows API manuals delivered with Visual C++ 1.0 back in 1992 (which I got as a present from my wife, though she wasn't my wife at the time. At the time I had been leaning towards focusing on the UNIX world, and my primary development environment was DJGCC, so it was an interesting change of focus).

Today's parallel of the bookshelf metric is the search-efficiency metric. Instead of simply measuring the number of pages referencing a given platform (such that the TPCI index does. I'm very cynical of measuring gross references simply because some languages have a lot of noise and bluster but extraordinarily little real world use. Hype languages generally feature a million beginner and advocacy pages, but close to no advanced or even intermediate pages), the search-efficiency metric is something you inevitably observe as you confront normal questions and impediments with a platform: How easily can you find answers to questions you face getting started, and then doing real-world development?

I've been a believer in the search-efficiency metric for some time.

Back when .NET was going through alpha and beta cycles, a peer advocated that we immediately drop all of our current development (on a mature, well-supported platform) and transition over. I was completely against the idea. Not because I didn't believe in .NET, but rather because some cursory analysis led me to believe that we'd be pioneers in many realms, basically clearing the path for future developers. That wasn't something we could afford with a tight deadline and demanding customers.

When .NET matured a bit, and a good archive of information detailing people's common problems and concerns, and their implementations of common needs, we could catapult forward.