there are general techniques for "seeding" search terms.

Obviously the best approach is to have someone manually do it who understands the space to initially seed it. However, its hard to get a really nice long tail of keywords that way.

The way to do something like this in an automated fashion would be to just find the competitor products and use something like SEM Rush to deduce what keywords they're hitting, then use a keyword expansion tool to expand that list.

After the initial setup, you should always be spending some of your adspend on expanding your keyword list. for example: 80% of your budget goes towards "exploit", which tries to perform as optimally as possible, and 20% of your budget goes towards "explore", which is basically letting Google and users give you hints about what words might be profitable.

To do this, create another campaign with broad match keywords (google matches a bunch of crap to these). Your script should regularly take the queries that match the broad match terms, then either:

(1) negative match it so you never see it again, for bad keywords

(2) exact or phrase match it to be managed by the CPC bid optimization method described in the post.

http://www.wordstream.com/products for example does some of this (and google itself will give you keyword recommendations)

Another keyword match tool is HitTail, but its effectiveness is diminishing as Google locks down search keywords:

http://www.hittail.com/

There are lots of automated bidding and keyword management tools out there on the market. The two biggest ones are Marin software and Kenshoo at the enterprise level. What they provide is both keyword analysis and expansion but also algorithmically driven bidding based on your defined goals. You can set it to maximize sales, revenue, or profitability. It does this by basically experimenting with different bids to achieve various positions for the ad and then models out the expected profit at different bid levels.

Another thing these tools do is incorporate your own sales data automatically via tags or offline data merges and use that for getting accurate revenue and gross profit metrics.

"Optimizely for Adwords" = Adwords. They have added very powerful tools for setting automated bid rules, little to no programming required. Developed ad markets mean the terrible keywords are cheap and the great keywords are expensive. If Google really is charging you 1 cent more than the next highest bidder you don't need to put in very much effort.

You can even just bid by CPA. Google figures out the rest (and they know how much you are making but that is another issue.)

The optimization that matters the most now is simply out earning your competitors.

Yeah, the trouble with CPA bidding is that you need to figure out how much you are willing to lose though. If you set your Google CPA at your actual CPA, then you won't make very much money. If you set it too low, you'll get crap traffic. The innards of these systems tend to be pretty complicated, so it can be hard to figure out where to bid.

Don't work for Google, but have worked with various bidding engines over the years.