In terms of Juárez, I think Sarukhán's point is valid, but targeting police officers who are the criminals' enemies doesn't itself eliminate the message to the public, which is to be afraid. It's hard to know for sure, but the selection of car bombs instead of AKs as the weapon for the attack would seem to be a conscious decision to sow terror among the population. But the clearer example is in Torreón, which was discussed in a typically bombastic column on from Martín Moreno. Partly because it's a lower profile town than Juárez, and partly because bombs are scarier than bullets, the mass killings in Torreón have gone largely unnoticed, but 40 innocents have been killed this year not because of any gang affiliation, but because they chose to have a drink in a certain venue. The targets were the civilians. The goal of the attacks was to kill them by the bunch, and to scare the rest of us away from certain bars. And it's worked; there are basically no nightclubs open in the town.
For reference, here's a definition from the UN regarding terrorism:
Criminal acts intended or calculated to provoke a state of terror in the general public, a group of persons or particular persons for political purposes are in any circumstance unjustifiable, whatever the considerations of a political, philosophical, ideological, racial, ethnic, religious or any other nature that may be invoked to justify them.
There's also a US definition that focuses more on political motivations. You could make an argument that the drug dealers don't qualify because their killings aren't political, but such a semantic argument just confuses the issue. The goals of the Torreón killers were to kill noncombatants and provoke fear.
The tactic of targeting civilians in Torreón doesn't seem to be spreading nationally, and Mexico isn't turning into Colombia. However, we need to call a spade a spade, and react accordingly. Until this week, Torreón hadn't had a federal security presence since last year, despite terrorist tactics being employed on various occasions going back to January. If Mexico's worried about the Colombianization of its security situation, pacifying Torreón and punishing the gang behind these killings should have been one of the government's highest priorities. Instead, it sent the message that you can intentionally kill civilians by the dozen, and as long as you don't score big-time media attention, you don't have to worry about the Mexican government.