Over the past several years I have followed numerous terrorist incidents as they happened through public media sources.

After last night's attack in #Vienna I have come to some conclusions as to how this kind of information has changed. A thread :

- Social media has become the dominant source of immediate information for the public during an attack.

- The quality of information available on these platforms has plummeted.

- The drive to gain engagements amplifies dangerous disinformation at critical junctures.

As the attack unfolded the local police force issued a vast array of tweets in multiple languages. One of the most prominent being a request to not share any videos or images of the attackers.

The logic was simple. These attackers would be able to use media coverage (incl. social media) to ascertain police movements relative to their own position. This is what happened during the Mumbai attacks in 2008.

This request fell on deaf ears and eager fingers.

Footage and images continued to circulate, tweeted and posted by private citizens and by news agencies and independent reporters.

Concerned citizens began tagging these posts with the Vienna Police force's social media handles.

This in turn resulted in the police spending critical time engaging with those spreading this content requesting that the content be removed and that it be sent to them privately.

As a result updates from this account, a key source of credible information became sparse. This resulted in a vacuum of reliable information. And into that vacuum came rumour and misinformation.

The first source (that I came across) suggesting that there was an ongoing hostage situation in a Hilton hotel was from this account.

Throughout the night this account and others like it tweeted an array of announcements as to what was going on. Filling this information vacuum.

These included:

- Between 7 and 10 fatalities.
- The use of IEDs or a suicide vest.
- Images of individuals identified as the attackers.
- Affiliation of the attackers (Hamas, al Shabab, ISIS, Turkey, Chechnyan)

Almost all of the above is incorrect.

The police, no doubt aware of the misinformation cascade underway on multiple social media platforms attempted to wrest back control.

Their calls for restraint, critical examination of media, and a halt to the spreading of further misinformation was lost in the rising tide.

Videos and media were now being injected into this void of credible information that had nothing to do with these attacks, or even Vienna.

One piece of footage, of police chasing down a fleeing suspect, circulated with various accusations of its original filming location.