In May 2011, a US Magistrate Judge talking at an eDiscovery event in London said that email's days of dominance were numbered. The next phase, he said, would be dominated by people sending short messages to each other and chatting. It would make discovery extremely difficult.

That was two months before Snapchat launched. WhatsApp was two years old. Instagram was a year old and did not add messaging until 2013. Slack launched two years later. The judge's comments were prophetic.

Back in 2011, people still wrote in whole sentences on a handful of formats and platforms, and IT still had some control of the devices attached to networks. But SMS, launched in 1992, was forming an ever-larger proportion of communications, aided by phones and tablets with keyboards. Simple messaging grew into real-time conversations, which could be private or public, in closed groups or open to all. Communication platforms crowded the market, whether dedicated (like WhatsApp) or supplementary to other functions (like Instagram).

Pure text turned to images - emojis, emoticons and photographs increasingly conveyed meaning as well as illustration. Sub-cultures used their own "vocabulary" of emojis and emoticons, and it became necessary to interpret these, particularly in criminal matters. Tone and implication were conveyed by the choice of emoji.

This raises a host of discovery implications. Is it suspicious that a conversation switches from email to WhatsApp or SnapChat, or was that just convenient? If a conversation suddenly stops, is that because the participants ran out of things to say or did they switch to some other medium which you don't know about? Does a particular emoticon affect the meaning of the surrounding text or did it just look pretty to the sender? Both relevance and interpretation became much harder to determine.

Forensic technology experts did their best to interpret the data, with new tools emerging, and a focus on behaviour and context as well as the actual messages. It became possible to use communication patterns pre-emptively, to anticipate security breaches, criminal actions or riots, and not just take a retrospective stance for discovery and investigation. However, users were always one step ahead and volumes shot up. Where everyone is using messaging for everyday purposes, how do you find the communications which are relevant between the custodians who matter?

The task of picking out the relevant from the irrelevant was therefore made harder by the multiplicity of platforms, by ease of use and by ever-increasing volumes. Then came COVID-19 and lockdown.

The first and most obvious effect of lockdown was to distribute people away from their offices and regular meeting places. They could not wander into the next room to ask a question, shout across the partition to their co-workers, travel to meetings or meet up for coffee and a chat. They were removed from the scrutiny of their managers, security cameras and even IT. They found other ways to communicate - not just the via the semi-formality of email, but by whatever device and platform came most readily to hand. Chat, in all its forms, is perfect for this.

The resulting communications are no less discoverable than anything more formal. A contract may comprise a series of messages where no-one is trying to hide anything, just trying to close a deal. A broken-up sequence of messages across different devices may conceal a fraud; it may just be idle chatter.

How do we deal with the growth of communication channels? It is perhaps an exaggerated version of the discussions we had when BYOD (Bring Your Own Device) was new – where an information governance or HR matter develops into a discovery review, magnified by the proliferation of channels and complicated by growing concern about security and privacy. It is difficult to enforce rules which require people to use only work channels for work communications, but you can at least employ the rules and specify the reason for them and the penalties for breach. You can also make it easy to comply with them for genuine work purposes, perhaps by offering chat tools which are user-friendly but which can be monitored.

Discovery tools for mobile devices are improving, some of them enabling cloud access to data which would be barred by lockdown. Even those who are willing to have their devices examined are not keen to hand them over while they are working from home at a time of infection. Review platforms now allow the review of communications data and chat alongside more conventional formats like email.

In summary, chat was a growing discovery problem which has been exacerbated by lockdown and working from home. It needs to be addressed pre-emptively as a matter of good governance, and its solutions lie in having the right tools in the hands of people who know how to use them.