I admit, I am a novice when it comes to running PPC campaigns. I can set u fancy tools to track your PPC efforts, make dynamic landing pages, and probably even dynamically adjust prices based on the average CPC prices (hmm, new idea for a product). But when it comes to setting these campaigns up within the AdWords framework and understanding how to effectively choose between the different match types (broad, exact, phrase) makes me a bit confused.
Let me first explain what each match type does, to the best of my knowledge: Broad Match: The default option for all keywords, if you enter "widget" into your keywords box, then you should come up for all sorts of widgets. You would probably come up for "blue widgets", "red widgets", "widget" without the s, and probably keywords that are like widget. So you need to be careful with this for two reasons. First reason is, if you don't sell "blue widgets", you will be paying for clicks when you don't have that product to sell. Second, sometimes if your keyword is strongly associated with a brand name that is trademarked, you might find yourself bidding on someone's trademark. Phrase Match: If you select this option with a keyword phrase in the format of "blue widget" then you will only come up for blue widget. The order and spelling is how phrase match works. It will also look for broad matched combinations of "widget" but only if it includes "blue". Hope that makes sense. :) Exact Match: This is probably the most tight form of the matches. So if you use [blue widget] then you will only come up for blue widget, and no other permutations of widget or blue. Negative Keywords: This match type is helpful by excluding trademarks or styles/colors of product that you don't sell. -blue would stop you from ranking for the keyword blue widgets.
There is currently an interesting thread discussing the benefits of using the different match types. In that thread, you can find some neat ad copy tricks. Please find the thread at Search Engine Watch Forums.