RhinoFish - 4:55 pm on Nov 15, 2012 (gmt 0)
concur with KimClink.
suggest you keep it somewhat narrow too, 5-25 keywords - the keyword granularity isn't super crisp like search, it's still thematic in nature, they've just figured out how to tag a single keyword as being the most relevant kw to that page's contextual matching action.
also, on neg keyword side, keep it slim. first 50 negs are used, again not perfectly crisply. more than 50 negs, it randomly picks out 50 to apply.