Another view of terrorism, in some ways similar to Nechayev's (in that the goal is revolution), is that it is an amplification attack. By committing acts of terror, a group forces the government to respond with stricter laws and more aggressive enforcement. Eventually, citizens who were not affected or inconvenienced very much under the original regime become significantly affected, and so they begin to oppose the government and support revolutionary causes, even if they are normally in favor of law and order and opposed to violence.

I believe this is the functional element of all terrorism, whether it is explicitly acknowledged or not. However, if that's true, not all terrorists recognize it; their goals might not be aligned with the ultimate consequences of popular revolution.