Robert_Charlton - 7:24 pm on Oct 8, 2012 (gmt 0)
g1smd - Thanks for re-posting. The thread you refer to is...
Google: 65 Search Quality Changes For August and September
One of the search "quality updates" announced by Google involves this one...
#82407. [project "Other Search Features"] For pages that we do not crawl because of robots.txt, we are usually unable to generate a snippet for users to preview what's on the page. This change added a replacement snippet that explains that there's no description available because of robots.txt.
That's led to several questions by members here, and we're encouraging those to be posted in this thread, which has already covered much of the ground.