the Automated Content Access Protocol (ACAP) recently has been released by a group more or less exclusively made up of publishers. it is kind of a
robots.txt on DRM steroids, a set of rules how content providers can tell search engines how to index and re-distribute content.
publishers these days have a problem: they need to be visible (i.e., they want search engines to crawl their content), but they also want to be visited (i.e., they want to drive traffic to their sites). this is a very delicate balance, because if you are too visible, people read the content elsewhere, and never actually visit your site. so even though publishers don't own the search engines and want to be visited by their crawlers, they also want as much control over the search engines as possible.
the ACAP web site boasts slogans such as
Improving universal access to content and
Unlocking content for all, which is kind of funny when you think about the fact that ACAP is mostly about controlling and restricting access. of course, ACAP also contains parts that should help search engines to do a better job, but my impression is that search engines are doing just fine without ACAP, and will continue to do so.
this is not to say that the current state of affairs is perfect or even close.
robots.txt is an old and fragmented
standard, and it is less than well-defined these days. so coming up with a unified way of how crawlers should be controlled would probably be a good idea, but ACAP and its generally publisher-focused attitude is unlikely to be successful.
lauren weinstein, andy oram and james grimmelmann have published interesting articles about ACAP (grimmelmann's article even features a detailed reply by ACAP's main author). most features of ACAP simply seem to extend the control of publishers beyond their web sites. they could, for example, specify that some content must always be displayed with license and/or credits information, or that only thumbnails can be displayed. this of course would be very attractive for the publishers, and it certainly open up a whole new world for lawsuits based on ignoring ACAP rules.