Pew's teen discussion groups have highlighted, as has other research and anecdotage, what the researchers describe as a "waning enthusiasm for Facebook, disliking the increasing adult presence, people sharing excessively, and stressful “drama”.

Many teens are moving on to Twitter whose use has grown significantly. Pew reports that 24 per cent of online teens use Twitter, up from 16 per cent in 2011. And they seem to be being more selective over who they follow (befriend on Facebook), with the 'median' teen Facebook user having 300 friends and the typical teen Twitter user just 79 followers (and a proportion of those presumably celebrities).

But the interesting thing is that the adoption of Twitter doesn't mean the casting out of Facebook. It appears (and my own discussion group of three teen daughters bears this out), that sites are collected rather than adopted and discarded. When asked, teen users say that while they are disenchanted with Facebook themselves, they keep up their profiles. Why? Because Facebook is the accepted way of maintaining your presence and broadcasting your 'status', even when you don't actively post and comment every day.

This realisation (that users may tend to collect social media more than they switch between them) is already changing the way the social media sites see themselves drumming up business. Once they have you the real task is on: to get you to engage as much as they can by using every trick in the book - from slightly erroneous information about messages you are supposed to have received, to full-scale explanations of what's in it for you if you adopt x or y feature - building engagement is what it's all about.

I suspect, from all the communications I receive on the topic, that this 'collection' dynamic has yet to be fully understood in the allied world of messaging services. The proponents of Joyn (the telco standard RCS messaging service brand) are fixated on the idea that users want to have just one message service so they can reach everyone. For some users that's no doubt the case, but many more (including the teen demographic) seem to rather like the idea that different messaging services exist for different groups of friends or contacts or interests. They don't want one service, they want a diversity (no matter what they say to researchers).

Other interesting things brought to light by the Pew study include:

Teens are sharing more information about themselves on social media sites than they did in the past. For the five different types of personal information that we measured in both 2006 and 2012, each is significantly more likely to be shared by teen social media users in our most recent survey.

60 per cent of teen Facebook users keep their profiles private, and most report high levels of confidence in their ability to manage their settings.

Teens take other steps to shape their reputation, manage their networks, and mask information they don’t want others to know; 74 per cent of teen social media users have deleted people from their network or friends list.

Teen social media users do not express a high level of concern about third-party access to their data; just 9 per cent say they are “very” concerned.