24/02/2014 08:02 GMT | Updated 25/04/2014 06:59 BST

Personal and Anonymous Social Networks Gain Ground on Facebook and Others

The science of Dunbar's Number is one that most of us are unfamiliar with, but the number itself is one that people in social media know very well. That number of 150 alleges that these are the maximum number of people or friends that a person's brain can deal with.

That is predicated by Dunbar's formula, based on analysing brain sizes of 36 primates and approximating that 147.8 is the 'mean group size' for human beings. Whenever a new friend is added to somebody's network, it means that an older friend has to drop out.

Dunbar himself is Professor Robin Dunbar and a UK anthropologist, and this notional number of 150 is controversial for many reasons. But what is rather more certain is that for people connected on Facebook, Twitter, LinkedIn and even the newcomers of Google + and Pinterest, these overburdened networks are being replaced themselves by more personal and anonymous networks.

Increasingly, this connection is happening on mobile devices and is defined by more than a static follower or 'friend'. The recent $19 billion purchase of WhatsApp by Facebook only underscores how the old social networking favourites are bolstering their position by buying into this trend.

These new networks take many forms, some are similar to SnapChat in their anonymity and short-lived nature. While SnapChat will delete images and videos sent to their networks, others apps such as Howl are using the contact numbers of the mobile phone itself to create a personal network and consequently coming close to the magical Dunbar Number in doing so.

The Howl app was built on the top of the Foursquare API and not only features some clever video marketing around two pandas and a pack of wolves, it also follows the way that wolves act in a pack.

A 'pack leader' creates various packs or personalised networks from the contacts on the phone then invites selected friends/wolves to join in on a night out. Again, like the dating app Tinder, users can swipe left or right with just one tap to say yes or no to joining in, or can engage their networks; so the more the merrier.

Howl isn't the only emerging app that is making waves in making socialising more personal, intimate and interesting. Based in San Francisco, Whisper is an app that lets users post their secrets anonymously, in an updated way of speaking to a priest during confession.

The company has already raised more than $25 million in funding and according to founder Michael Heyward, the company has millions of people using his service. Seen as a rebuke to networks such as Facebook, and especially LinkedIn, where users self-curate themselves to a (literally) unbelievable degree, Whisper is a platform that is a place to let off steam; it is also addictive and likely to become wildly popular.

The need for secrecy and anonymity also stretches to secure email. Working across Gmail, Yahoo! and Outlook, Virtu lets users keep all private email communication secure. Rather like SnapChat, emails can be deleted at a certain posited time and can be shared with certain networks with permissions that can be deleted at any time.

Then there is TimeAppsule, a time-locked gift and greetings service that takes its inspiration from the time capsule model where content and products are buried to be seen at some time in the future.

In this instance, users can store selected gifts such as photos, video and voice recordings to be stored, locked and sent to a chosen recipient for a specific date and time for up to 12 months in the future.

No more late gifts again, and this one has a touch of class about it... for certain people. One for 149 friends perhaps, but a little cheap for the special one in your life.

Finally, Secretly Meet is a beta site that allows users to set up and work with temporary websites that only exist when the browser is turned on... and disappear when the browser is turned off.

This peer-to-peer communication via a browser means that information can be shared privately and confidentially, obviating the need to send sensitive data through a server or Third Party computer.

As these apps and services begin to proliferate, the purchase of WhatsApp by Facebook for such an astounding amount begins to make sense. Rather than be usurped by the Young Turks such as Howl, Whisper, Virtu, TimeAppsule and Secretly Meet snapping at its heels, Facebook may have made the smartest move of its history.

For follower of Dunbar's Number, the mathematics and science is easy when it comes to the rise of personal and anonymous social networks. The magic number may be 150, but perhaps in a few years' time, that will be the number of such networks people are using, not the number of friends that they maintain.