People have been describing the Cecil controversy as "an Internet hate mob". So far as I know, however, this was something more normal: the media picked it up from people in Zimbabwe and reported it.
It's just generally unlike the other hate mobs:
(1) There's an actual crime involved, namely poaching, which has been essentially confessed. Previously we've been talking about hate mobs after someone in a photo posted to Facebook, a person with an opinion, or a YouTube video. That is, where the Internet creates notoriety where none should have existed. This was reported in major media because it's actually a major scandal.
(2) This started in the press. So far as I can tell, the source of controversy was the British press, which reported on it and erroneously identified the hunter as Spanish. Previously we've had a narrative more like this: the Internet sees a photo or video posted by Just Another Person and it goes viral because people are offended, ending in some person with normal levels of thoughtlessness hounded into the hills. In this case, there's the implied level of thoughtlessness, or possibly outright douchebaggery, which warrants media attention.
(3) The mob is tied to the media, not making its own conclusions. As the media reports on it, the mob shifts focus. Had they reported instead that Zimbabwe had permitted it, outrage would be directed at Zimbabwe -- permits name a specific individual. That's an old school mob, not some new-fangled Internet mob.
I'd note that we've been consistent before in placing the blame on the media when this happens. After all, their reportage comes bound up with some credibility. It's likely that, without media involvement, nothing would have been said about this at all. It's not as if Palmer hadn't been posting pictures already nor as if people don't post pictures of things they've shot, lions included.*
That's not happening right now. Media sources are now characterizing it as "an Internet mob". I suspect this is just poor reportage. But we have to be careful with assigning blame. This doesn't appear to be "an Internet mob", it's a normal mob created by normal media. That its organizing over the Internet rather than spreading through conversations in person doesn't change the essentials.
*Personally, I'd prefer a "no hunting" toggle in Google image search so I don't see any of these disgusting tributes to the vanity and destructiveness of people.