I recently added all the webmaster type searches to one of my campaigns where there is a lot of optimization going on, such as:
-site
-url
-allinurl
-link
Then thought about it, because of this thread, post 9:
[webmasterworld.com...] (and if you're wondering how to easily search WW, read the post).
and added:
-googleguy
-adwordsadvisor
-adsenseadvisor
(Did you guys think you'd be -KWs?)
Dropped my impressions by 15%, clicks by under 1%, and conversions by 0%, so I received a decent raise in CTR out of it.
Any other good global negative KWs out there?
Brands I don't sell:
-sony
-panasonic
People looking for wholesale:
-wholesale
-importer
Image hunters:
-image
-pic
-picture
Price modifiers: (depending on my offer)
-cheap
-best
-discount
Information gatherers: (some will argue here)
-review
-rating
-comparison
I'm always sure to include all the stemmed variations of the above as well.
But going by the stats of a large number of campaigns, you can expect to lose out on approximately 50% of the traffic.
I use pretty much only exact matches - and I guess I miss out on 50% of the traffic - but the 50% I retain is more targeted and likely to buy. It's more work - but it is worth it IMO.
I have setup two campaigns for the same keyword. One is exact match, the other is broad match. If you setup the exact match campaign first you will find that both campaigns will get traffic and you can modify your broad match bids down as needed to respond to the lower conversion.