<meta name=”generator” content=”Adobe GoLive 4″/>
<meta name=”generator” content=”Microsoft FrontPage 4.0″/>
<meta name=”generator” content=”Mozilla/4.7 [en] (WinNT; I) [Netscape]”/>
<meta name=”Generator” content=”Xaraya :: .903″ />
it seems it is 8 years too late to define a best practice format. the consensus seems to be, as roger pointed out, productname/version
quite a few tools already utilize the meta generator tag, although its use seems to be much more common on the html authoring side than on the cms side. time for a survey, and spreading a little RFC.