Thus, and despite having read all the enthusiastic threads here on power posting, I still don't understand the use of the time spent on fine-tuning and doing a cost-per-click for each keyword. (I can see the purpose of sending specific keyword-searchers to specific pages).
?
An adgroup has a max CPC of $2.00 and has the following keywords
Blue Widgets (avg position 2.4)
Green Widgets (avg position 3.1)
Black Widgets (avg position 8.5)
In the above scenario, the keyword "black widgets" is shown in the second page of the search results. If you increase the max CPC of the entire adgroup, your overall costs will increase since it affects keywords blue and green widgets too.
If you use powerposting and set the max CPC of "black widgets" to $2.50, you can make sure the ad appears in the first page of search results for the search "black widgets". At the same time, it ensures that the costs of other keywords in the adgroup do not change.
Makes sense?