I've been reading thread after thread, and one thing keeps popping up, no matter what the topic is: suddenly, google is buggy.
Since my main concern is Adwords, and since I've seen, and participated in the various threads concerning adwords bugginess, I thought: let's make a list. Let's all post some of the bugs we've seen. Maybe we can come up with solutions for each other. And maybe, just maybe, Google will see this and make some corrections.
So, for my part:
* I've bid on keyword "widget service" for over a year. Always #1. Always 3-5% click through. Impressions averaged 300-500 a day. Suddenly, overnight, impressions jumped to 10,000 a day and more.
* Noticing the above, I put on phrase, and then exact match for that keyword. Lo and behold, the impressions actually increased! How that is possible is beyond me.
* Quick note: phrase matched terms don't show up on AOL, only google. Maybe that was always the case, but if so, I missed it.
* Finally, I return the term "widget service" to broad match, and suddenly the impressions are normal, but my click through rate is over 10%. I kid you not.
* Also, terms that got x number of impressions for over a year... very consistantly... are suddenly getting 2x impressions. Others, which got x number impressions consistently are suddenly getting 0.3x.
Please add things you have seen. I think if we add all this up (even if our experiences are not the same) the volume alone of bugs should add up to prove that they've changed something on AdWords/Google/AdSense, and it's messing everything up.