The US stock market is in the middle of its second quarter results season, and on balance the figures trickling through look pretty good.

The average year on year growth in earnings is about 20% (the level anticipated by analysts beforehand). This is a bit below the 26% average growth of the first quarter, but nevertheless represents a good pace of progress given the big rebound from the last recession and the length of the current cycle.

However, there has been one notable large-cap US exception, with Facebook dropping nearly 20% on Thursday last week.

The loss of market capitalisation was $120bn – more than the current value of blue chip industrial General Electric.

Newspapers, magazines, and generally all those involved in the print industry, which has been decimated by the likes of Facebook, will be experiencing a certain amount of schadenfreude (that wonderful German word signifying enjoyment of other people’s misfortunes) in the share price reaction.

Facebook’s Q2 revenues grew 42%, but this was seven points down from the Q1 growth rate, and the company indicated a likely deceleration over the mid-term to levels in the mid-twenties.

The management has put this down to currency, new advertising formats, and privacy (the recent GDPR regulations and the fallout from the Cambridge Analytica scandal seem to be having an impact).

The management was also downbeat on margin progression. The company has managed to keep operating margins above the 40% level consistently over time, but now suggests that these will drop into the mid-twenty levels over time.

The shares had derated to some extent over the past year, with some suggesting they looked ‘good value’ on a Price to Earnings, or P/E, basis. But the Price to Sales ratio still looks high at ten times historic levels, even after the fall in the shares.

The Financial Times on Friday produced graphs of the quarter on quarter growth in daily active user numbers, which show a decelerating trend across all markets, even Asia and the Rest of the World. Growth in daily active users in the US has fallen to zero, and is even slightly negative in Europe. Is this sign of ennui, of people finally getting fed up of the site?

My own (admittedly intuitive) observations would seem to bear this out. I sense that the cohort of users that got involved for the first time five years ago are still going strong. But the cohort of early adopters, who first got involved 10 or more years ago, seem to be dropping off (who knows why – rehab, saturation, boredom?).

In contrast, the other big US internet businesses – Amazon and Alphabet (formerly known as Google) – produced top of the range figures last week.

Could they have more resilient models – less immune to fad or fashion changes?

People use Google because they want information. People use Amazon because they want to buy something cheap. These desires aren’t likely to change.

Why do people use Facebook? Essentially for the same reasons that people used to read newspapers, because they want to be informed or entertained, and a few targeted adverts get chucked in along the way.

The difference is that the ‘disaggregated’ model of Facebook implies a newspaper but perhaps not one that is ‘edited’ in any conventional sense.

The authorial tone of high seriousness that the broadsheet newspaper editor traditionally imposed on a publication has gone out of the window. The entertainment element may be high, but is it cloying? And is one being accurately informed?

Facebook won the ‘network effect’ war over rivals Friends Reunited and Myspace, proof that ‘First Mover’ advantage doesn’t always work. It has also cleverly bolted on the social media sites aimed at the next generation. So it is unlikely to get replaced. But it is not inconceivable that people at some stage grow out of the habit, or decide they want a lifestyle change.

Another problem noted by some analysts from an ad growth perspective is that Facebook may have cleaned up all the ad dollars going into print advertising, but it hasn’t shown any ability to cut into TV advertising revenues (as yet).

Truly, with its focus on self-promotion, celebrity and self-expression, Facebook is a medium for our times.

But its prospects as a money-making machine have suffered a setback.

The opinions stated are those of the author and should not be taken as investment advice. Any recommendations may not be suitable for all, so please contact your financial adviser for further guidance. The value of investments can go down as well as up.