I believe that this matter does present serious ethics violations -- but by Kelly, not Frey. For starters, there's the matter of Kelly threatening to take an ethics action against Frey when there seems to have been no legitimate basis for doing so. But more importantly, what kind of a defense attorney, when confronted with evidence compiled by a reputable blogger (who is a prosecutor, no less) wouldn't at least contact him for additional information? After all, recall that the Durham in Wonderland blog put the spotlight on the many prosecutorial improprieties in the Duke Lacrosse case. Perhaps I could understand if Kelly was concerned that Frey's posts would tip off prosecutors. But again, the appropriate response would have been a phone call, not a threat of an ethics charge.
In this day and age, no lawyer can afford to ignore leads (or at least seemingly credible leads) generated through blogs. Providing those leads as Frey did isn't unethical; disregarding them as Kelly did is.
I haven't researched the issue whether Kelly's actions violate any ethics rules, and thus won't take a position on the matter. But Elefant's second point -- that attorneys can't ignore the blogs -- is certainly well-taken. Still, there's something a bit surreal about an attorney who is representing a death row inmate debating issues that could potentially save her client's life deep in the comments section of a blog.