Riccò didn't snitch to the authorities. Riccò named some already well-known people and was thought to be evasive, hence why he had to appeal just to get the four months knocked off his ban. Sella named his sources and detailed many a thing and it got to the point where busts were happening in Italy and Sella was coming forward and saying "nothing to do with me!" because he'd detailed enough that much of the Italian continental péloton were of the "if in doubt, blame Lelle" persuasion. He now rides like an Italian version of David Moncoutié (in terms of his positioning in races, not in terms of anything else, as they're obviously from very different ends of the Clinic scale) - either right at the back of the péloton or in the breakaway. It's harder for the saliva to reach him there.
It'll be interesting to see reactions when Valverde returns. He was an absolute pariah on this forum, and plenty of people who were pro-Vino and pro-Riccò were going apoplectic and treating Valverde as if he celebrated his victories by kicking puppies and holding up depictions of Muhammad as he crossed the line.
Millar? Millar's a "do as I say, not as I do" kind of character. He has managed very well to peddle a line of being the reformed white knight. But there's no convert worse than a zealot, and there's no zealot worse than a convert. His act is pretty transparent, and to tell the truth has done very little to undermine omertà if anything at all, and his smug preaching whenever asked about any case is hypocritical at best, downright insulting at worst.