After finally achieving 30 cents per download (where AdWords is actually profitable) and keeping it there for a week my CPA creeped up again to 37 cents. Since I hadn’t made any big changes to my campaign and my market is pretty stable this time of the year I investigated what was up. It turns out that Google turned off half of my words in the vocabulary campaign, requiring a minimum bid of 15 cents for what used to cost 7-9.

This leaves me less than happy.

Some of the words were pretty borderline when it came to click-through rates, in the 1-2% region. Of course, they were also getting 3rd/4th position so I’d consider that decent. The other words were nothing like borderline: I got my cost doubled on “Dolch sight word bingo”, of all things, which is a) 6% CTR on a bad day and b) my landing page for that is human-generated and about as responsive to the query as you can possibly get.

It could possibly be eBay et al upping their CPC prices across the board (my only competition for AdWords is people bidding on gigantic portfolios, ranging probably in the millions of search strings), which means I just got priced out of the market, but unless their computers really like increments of 5 cents I’m guessing it was Google assessing the low-quality penalty rate. Which is indescribably irksome. I’ve sunk dozens of hours into optimizing that campaign to get it where it is, and I don’t think its even mathematically possible to make it have positive returns at the new-and-improved CPC rate.