Beside the obvious marketing spin, how do you define an "expert software designer"? I remember a long time ago in the pre internet era someone defined an expert

Beside the obvious marketing spin, how do you define an "expert software designer"? I remember a long time ago in the pre internet era someone defined an expert as "anyone 40 miles from home". How am I supposed to evaluate someone's opinion as to whether or not I should even pay attention to their habits?