It's like looking for a needle in a haystack - the hard part is finding the needle, what's easy is verifying that what you have in your hand is a needle.
Of course in real life this is probably some sort of misinformation campaign to try to misdirect from the fact that they have some sort of informant or other means of figuring things out that they want to cover for.
The implications of something like this are interesting - it's just a graph theory problem, and hypothetically the computer could be programmed to automate a drone strike when a location reaches a certain score threshold.
In this specific circumstance, it appears they got the right target.
This incident has created the need for ISIS to have disinformation campaigns disseminated on social media by people who would be targeted by the strikes-- they can easily implement a policy in which they allow themselves to have a digital footprint in certain irrelevant areas in order to bait an attack, creating civilian casualties and bringing in new recruits.