Unfortunately there is no non-gross website with decent reporting on the Kannagi stuff, but the reliably loathsome Sankaku Complex has some reliably thorough coverage: http://www.sankakucomplex.com/2008/11/10/%E2%80%9Csecond-hand%E2%80%9D-nagi-provokes-otaku-storm/ and http://www.sankakucomplex.com/2008/11/15/cuckolded-otaku-desecrates-kannagi-over-virginity-issue/

FTR it got so bad that the manga-ka even received death threats from angry fanboys. It's disgusting.