The paper you mentioned appears to be saying that Microsoft is extracting spell corrections via clicks on Google. That's pretty surprising news.

I just pulled down the paper and noticed this: "The clickthrough data of the second type consists of a set of query reformulation sessions extracted from 3 months of log files from a commercial Web browser .... In our experiments, we "reverse-engineer" the parameters from the URLs of these sessions, and deduce how each search engine encodes both a query and the fact that a user arrived at a URL by clicking on the spelling suggestion of the query – an important indication that the spelling suggestion is desired"

Some of the recent discussion has been about whether Microsoft looks at lots of different sites vs. doing something special or different for Google. This paper very much sounds like Microsoft reverse engineered which specific url parameters on Google corresponded to a spelling correction? Figure 1 of that paper looks like Microsoft is using specific Google url parameters such as "&spell=1" to extract spell corrections from Google.

Targeting Google specifically is quite different than using lots of clicks from different places. It looks like you work at Microsoft--can you say any more about this?