It's amazing to think that a few short years ago "craft beer" sounded exciting. Now it's so old hat I could barely bring myself to comment when there was a brief return of the "what is craft beer?" debate recently.
All craft beer definitions have failed because they're simply unworkable. The "official" American definition endorsed by the Brewers Association is of no practical use when you've got your mitts on a beer as you're probably none the wiser about the brewery's share ownership or annual production so won't know for sure if it's craft or not.
What's needed is something that can easily be used by the average drinker and is based on assessing the beer in front of them. Though some quibble over technicalities about "real ale" if you see the beer pulled from a hand pump it's a safe bet that's what you're getting.
Unlike real ale though craft beer is not about the method of dispense, it's all about the flavour. And that flavour is grapefruit. No need to worry about share transactions or production figures, just have a swig and ask yourself "can I taste grapefruit?". If you can it's craft, if you can't it isn't.
This solves another conundrum too, as it shows some real ales are craft beer and some aren't, easily distinguished from each other by whether they taste of grapefruit or not.
Having this practical definition will easily allow normal drinkers to tell craft beer from non-craft, and still allow craft beer aficionados to have fascinating discussions about rare beer ("can you taste the grapefruit in this imperial stout?", "is this beer still grapefruity since the brewery's been taken over?"). This simple definition should settle things once and for all.