Five Tenets: Fluidity

This post is part of a series on the Five Tenets of a Modern, Multi-Modal, Real-Time Communications Application.


Fluidity is the subject in this second post on the Five Tenets of RTC Apps. RTC Fluid Conversations I define Fluidity as the ability of a single conversation to move fluidly between various modes of conversation. The most important modes are Chat, Voice, and Video. The graphic on the right illustrates how a single conversation may progress: starting in a text mode, the participants decide to upgrade to voice, and later to video. After concluding their video conversation, they drop back to text chat. Importantly, this entire sequence stays within the context of a single conversation.

Example of Fluidity

To meet the requirements of Fluidity, a Real-Time Communications App should present all the various modes in a single stream. A good example of this that many people may be familiar with is Skype. In the screenshot you can see where the conversation began as text, and then upgraded to audio. After talking, conversation continued via text. The user interface displays this the best way it can, by showing where the conversation changed modes. A more capable app might have recorded the audio and made the recording accessible inline in the conversation history.

Fluidity is also Portability

Going beyond simply changing the mode of communication is changing where the communication occurs. To meet the requirement of Fluidity, an RTC app must also allow users to move the conversation to the whatever device is most appropriate to the user. For example, I may start the conversation on my phone as I’m driving to the office. But when I reach the office, I want to switch to my desktop, which is more capable and may offer me more capabilities such as screen sharing or video. This allows users to make the most of Adaptability, as we described in the previous post.


Many RTC apps exhibit signs of fluidity today, including Skype in the example above. Hipchat and Slack also do a particularly great job of this, while others like Facebook Chat and Google Hangouts are obviously making improvements in this direction. My hope is that, in the future, the various modes will become more transparent and accessible. For example, instead of just showing that an audio conversation happened, recording and transcribing it will make the audio conversation accessible. Preserving this history will make communications in the future even more powerful and usable.

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