As first reported by Dr Vino, Randall Grahm of Bonny Doon has taken the initiative to put a full ingredients list on the back of his labels. In particular he notes the finings used (which may be of interest to certain strict vegans who prefer to avoid products fined with isinglass or eggwhite) and the concentrations of sulfites. This latter issue has long been a controversial one; some people have allergic reactions to sulfites, but a far greater number mistakenly think that they do. Until now all that people had for reference was the fact that wine labelled as "contains sulfites" typically contained anything from 10mg to 350mg (the maximum the FDA allows) per litre, and that anything not so labelled contained less than 10mg (since sulfites are naturally occurring products it's impossible for a wine to contain none at all). Note: Please see discussion under comments for more on this.
It's perhaps too much to hope that this becomes a legal requirement, but I hope that it takes off as a concept and other wineries follow suit. After all, the best winemakers ought to have nothing to hide. Plus of course it's also good to see a Santa Cruz Mountains winery taking the lead on this.