Users on En. are requesting the ability to add comments to watchlisted items,
for instance, to remind them about why they watched the item in the first place,
or to "tag" certain items, e.g. "featured", "vandal magnet", etc.
While I realise this might need an interface overhaul, I've also - literally
this second - thought of a fairly flexible way of doing it.
Anyway, here's the feature request, just so's I can assign it to myself when the
time comes. ;-)