I have always known the risks involved with using broad match terms in Google AdWords. Before there were search query reports, I would use the raw log files to see what people were actually searching for, and was often shocked at what I would find.
An example of this outrageous irrelevance would be if I were to have bid on something like remote desktop monitoring software I would sometimes get searches for just the word software. I also recall bidding on something related to shareware and getting searches for share market or market share.
Well lately, I have been really put off using broad match, as it seems as though there are a lot more irrelevant hits coming from broad matched terms. Another interesting item that I have noticed is that it seems as though Google try to make you ‘feel safe’ with broad match by way of conversion tracking. I have noticed situations where I bid on a number of very targeted phrase and exact match terms and a few broad match terms. The broad match terms sometimes receive far more conversions than the more targeted non-broad keywords.
You’re probably thinking that those phrase and exact match terms are most likely not what people are searching for, however this is not the case. When you run a search query report specifically on those broad match terms, you find that you are already bidding on the terms that are receiving the conversions.
It’s almost as if Google are saying, “Don’t worry that it is broad match and you get a few irrelevant searches mixed in. You can see that you are getting some conversions”. The problem is that if you leave this unchecked, the broadness craziness goes wild.
Note that I am not saying that you should never use broad match terms in your AdWords campaigns. My own rule is that I do not use broad match in campaigns which only target the content network. This is because you have absolutely no way to tell what Google are doing with your keywords, as there is no keyword data on the content network. I do use broad match in search campaigns but with great caution. I begin with phrase and exact match, then once I have data as to what people are searching for, I sprinkle in some broad match and closely monitor their performance.


Broad match is getting broader and broader, up to the point of being completely irrelevant.
Some examples from my Adwords account:
keyword: book database
broad match search terms:
- rs numbers of genes database
- kirjatietokanta
- isbn search
- jatropha literature
keyword: game database
broad match search terms:
- joc de table
- db simulation
- billiard table
- oyun ukletirmek
keyword: movie library
broad match search terms:
- to speak film
- martin scorceses filmarchive
This is going downhill fast. I started doing more broad match about 8 months ago and that was mildly succesful, especially combined with a good negative keyword list. But negative keywords can never fix the above mess…
I agree that broad match needs to be approached with caution, but think broad match is all to often looked upon in an undue negative light. Yes it does give you some ridiculous irrelevant searches (as Alwin rightly pointed out), but I’ve found the majority of searches are actually highly relevant. I think negative keywords can in fact fix irrelevant matching if used effectively, although broad match effectiveness is never going to happen overnight.