Still thinking about thumbnails to go with your online bookmarks (A del.icio.us makeover and Going Dotty). I prefer BlueDot's system that allows you to select a graphic from the page to use with your dot. My Songbird Media Player dot provides an ideal example. But what about pages that don't have a suitable image. Perhaps they don't have any images or the only images are ads. Then it would be great if you could use a screen grab of the page. No doubt this is a bit labor intensive to do on the fly on the off chance that you might want that. But perhaps it could be a distinct process that the user could initiate.
Another option might be that sites could provide a preferred image for use by bookmarking systems, in the same way that they supply a favicon (I guess a 'doticon' is going too far) . This would provide sites an additional opportunity to control their branding. Which is never a bad thing IMHO.