Beeing an early adopter is a way of living, not some marketing category. Either you do it in most aspects of your living, or you don't. In order for you to take up Linux or Mac, or use Firefox instead of IE, you have to get active. Purely by crossing that line you've placed yourself in group of people that care about their digital tools and search to improve them.
Funnily this kind of description would perfectly fit the bill of early adopters too. It's no coincidence there's a similarity. Linux and Mac users are deep early adopters, on the very end of the scale of how early adopterish they can get.
Thus the remark becomes:
Early adopters may be in the minority, but they are vocal.And now it's you, who'll go "duh!" on me. Because it's so glaringly obvious.
But consider, most applications that are written are for Windows. A lot of websites out there are only working satisfactory in IE. Thus the deep early adopters will avoid these products and projects like the pest, because it doesn't run with what they prefer from the depths their hearts.
We all know early adopters are important because they give you a kick start market, free marketing and a clear indication weather what you did rocks or sucks. If you throw a good percentage of early adopters away simply because you feel that their market is to small to be considered, you should consider that decision very very careful. It may prove fatal for your product.