A new service is available called Tagyu. A suggestion engine for tags. You can put it a URL or text and it will give you some suggested taggings based on others. Del.icio.us already gives suggestions now so I probably won’t use it much. A wordpress plugin suggesting tags (technorati) for posts would be nice, though I’ve been too lazy to tag posts lately. Web Service for Tagyu is coming soon according to the FAQ. Update: A web service interface is now available.