To be successful, PPC campaigs need to experience both a good click through rate (CTR) and a high conversion rate. First, users have to actually click on your ads. Secondly, they have to actually give you some business. If users are clicking but not buying, it's because your PPC keywords aren't being properly targeted.

If your keyword is too broad, however, your ads can end up places where they will not be relevant and, therefore, will not get clicked on. Although this won't result in a high CTR (and exhaust your ad revenues), it will mean that you ads are being shown to people who just don't care. In other words, even though your PPC campaign isn't costing you money, it is costing your marketing department time & resources that arent' generating any kind of return.

For example, one week ago, we posted about how the keyword Spam isn't a sufficient keyword for the makers of the canned meat-product. Well, Greywolf provides another example of keyword PPC ads showing up in strange places. He writes:

So the person’s name in the email happened to be “John." While the first two aren’t relevant I get how they got there. The bottom block on the other hand is a bit more perplexing. [...] Now Elton John doesn’t strike as a Gmail kind of guy, but I really don’t think it’s the Elton John any way. However my curiosity gets the better of me and I click away.

What Greywolf found after clicking was a page of sponsored results that included Elton John ringtones, tickets, and the rocker's official site. Since "John" is one of the most common names in the English language, it is probably too broad to be used as a keyword here. These advertisers might have been better off bidding only on the keywords "Elton" and "Elton John" as these are much more targeted keywords.