waynne - 3:22 pm on Jul 5, 2013 (gmt 0)
It made no discernible difference to me whatsoever. I added it for 30 days, removed it for 30 days and added it again for 60 days on 4 different sites/4 different author tags. Traffic levels were the same, click throughs were the same. No benefit whatsoever!
I still even have scraped content outranking me which I thought and would have expected an authorship tag would avoid!