A year ago the subject of attention wasn't getting much, well, attention. But that has been gradually changing, due in part to the efforts of AttentionTrust.org (disclosure: I'm on the AttentionTrust board, although I write this post as an individual), and also due to the growing realization that big players such as Google are benefiting from data that you generate for them.
In a previous post I described how companies such as Netflix benefit from your "attention data" (that is, information about what you're paying attention to) by recommending products based on what you've already purchased. That seems pretty obvious, but it may not be so obvious as to why a company like Google would want this information.
In Google's case, I think they're facing problems due to clickfraud, splogs and link spam in general. While Google certainly employs ways to protect page rank from link spam, it's an uphill battle, and it's got to be something that their advertisers are (or soon will be) concerned about.
For this and other reasons, what Google really needs to know is what people are actually paying attention to - not just what they're searching for, but also what they're clicking on and reading. This is where something like their Web Accelerator comes in handy, since it passes your page requests through Google's servers, giving them a way to find out where attention is being paid.
In general, I don't believe there's anything wrong with this as long as there's no deception about what's going on (and Google does make it clear that traffic is passed through them). But I also believe that you need to seriously consider whether you're being fairly compensated for what you're giving up.
Does Google's Web Accelerator benefit you enough to give them your attention data? In my case the answer is no, but I'd be willing to trade my attention data for free wireless access in my home town. Of course, your answer may vary depending not only on how valuable the compensation is, but also on whether you agree with the way aggregated attention data is being used.
The other thing you need to be concerned about is whether you can get your own attention data back. This is where most of the current crop of attention gatherers fail the test, since few of them provide any way for you to get the data they've collected in a way that enables you to use it outside their service. I'm not cynical enough to attribute this solely to greed, though - it may be because they don't personally identify the data they collect, or that they haven't considered giving back this data simply because very few people have asked for it.
If you'd like to persuade more companies to share this data with you, then I hope you'll consider joining AttentionTrust.org. The more people we have on board, the easier it will be to convince attention gatherers to not only give you access to information they've collected about you, but also to provide fair compensation for it.