It’s time to add a new method of electronic communication to the list of discoverable electronically-stored information.

Slack is a messaging app that calls itself “team communication for the 21st century.” The app lets users communicate in public or private chat settings, share files, images, documents and other data, and allows for the syncing and searching of other services such as Google Drive or Dropbox.

Slack uses hashtags—familiar to users of twitter—to organize and curate conversations into “channels,” e.g. #marketing or #sales.

It was created in February 2014, but it seems to have taken off in the last year or so. Slack is being used across Silicon Valley, according to Slack’s website, and is also used by government employees.

The app is marketed at companies and work environments, and it’s mainly used by employees to communicate amongst themselves and their teams.

Its chat function and ability to incorporate other services in its search feature makes Slack an eDiscovery goldmine, as well as a potential nightmare—all that information is in one place, but the siloing and searching of the data generated by and stored by those services could create headaches for parties if and when their Slack data is requested.

Slack’s privacy policy warns users to consider how their company or organization might use their Slack data, and how that data might be stored, accessed or retained.

Attorneys engaged in eDiscovery should consider the wealth of information that could be available from this new app—and should consider asking opposing counsel if their client #slacks.