.info domains were being experimented with to test for their relevance to spam. Heres the article: http://www.seobook.com/google-temporarily-purges-info-domain-names
I think it is not the only extension, it is only happen that more .info sites have more hits. There are still .info sites that already established good reputation and are not affected. Here's one: css3.info
Its about SPAM.. Not the .info domains. Besides, theres no official statement from Google about this.
If google sees a pattern they will adjust there algorithm to combat the spam. Theres no proof that they would put .info domains at a disadvantage because of the domain extension, but for georgraphic searches the domain name will be less relevant to a country code specific domain.