Samizdata - 9:33 pm on May 24, 2011 (gmt 0)
Anyone see any dangers with this?
Brett would correctly remind us that with Google there is always potential danger.
Six months ago I put in a similar .htaccess rewrite for Google Web Preview on one of my sites so that I could control my visual preview in the SERPs. It worked very well.
Following the clarification via the Instant Previews FAQ that this technique "may cause your site to be perceived as deceptive and removed from the Google index" I abandoned plans to implement the procedure across all my sites.
If it is the case that you are serving Google Web Preview different content to what GoogleBot sees, that would be what Mountain View calls "deceptive cloaking" and which is explicitly not allowed (by them): [sites.google.com...]
You must show Googlebot and the Google Web Preview the same content that users from that region would see (see our Help Center article on cloaking).
Interestingly, both the article on cloaking and Google's Webmaster Guidelines use a different form of words, stating clearly that cloaking involves serving different content.
Serving Google Web Preview a different response (e.g. 403) is not cloaking.