Your right people will only look at the things that interest them and the technology within Twitter, Facebook ect also helps narrow down what we "should" like.
However, other studies have shown that the average social media user can't get enough info and will be checking their profiles last thing at night and as soon as they get up. Why? Simply because there is always new information available, and a lot of users are afraid of missing out - even if they don't realise it.
I'm not actually sure if we should be cutting back or sharing more, and think that testing and analysing how your audience engages is the only way to find out.