Geofeedia isn't the only social media surveillance company providing information to local police departments.

Twitter shut off commercial access to Geofeedia on Watch Secret Boutique OnlineTuesday after the ACLU revealed that Twitter, Facebook and Instagram data was being marketed by Geofeedia to police as a way to monitor activists and protests.

Facebook and Instagram had also recently severed much of Geofeedia's access to their networks for the same reason. (Mashablealso uses Geofeedia to discover potential stories on social networks.)

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But social media surveillance companies are proliferating, and Geofeedia is not the only one that has seen an opportunity in marketing their services to police departments by telling police they could track hashtags associated with Black Lives Matter protests.

Media Sonar, whose website says it has "proven" to be a "powerful tool for assessing threats," was found to market their services to the Fresno Police Department, according to results of an investigation by the ACLU published in December, 2015.

The ACLU found that Media Sonar had enticed Fresno officers by suggesting police monitor hashtags such as #blacklivesmatter, #imunarmed and #dontshoot.

This, according to Media Sonar's co-founder who was not identified in the report, could "help identify illegal activity and threats to public safety."

The ACLU also found that Fresno police were using a social media monitoring software called Beware.

Beware, which markets itself as a service that can create "awareness of potential threats," can assign a "threat level" to a social media user based on the information Beware can gather from that user's social media profiles.

Beware can also attach a "threat level" to a person at an address at which officers are responding to a call.

Intrado, the company behind Beware, won't publicly reveal how it assigns threat levels.

Digital Stakeout, yet another company built on social media surveillance, was used by the Oregon Department of Justice to monitor activists using hashtags such as #fuckthepolice and #BlackLivesMatter.

For the ACLU, the concern is that this growing industry is yet another form of surveillance being employed without transparency.