Differences in the similar - the lack of a shared experience
In The Uses of Literacy, Richard Hoggart mentions people listening to a particular wireless programme because everyone at work will have listened and they want to be able to join in when people are talking about it. I remember something similar when Friends was first on British TV, with twittering groups of girls at school the next day saying 'did you see the bit when...?' (I wasn't one of them, but I'm sure you'd guessed that). I've watched a most annoying episode of Doctor Who just so I can talk about it with Big Brother later, keeping us in touch when we're apart at Christmas, but is there much of that left?
To stick with TV for a moment, there are so many cable, satellite and Freeview channels available now that it would be a big coincidence if a colleague had been watching the same programme as you (a friend with a certain amount of shared tastes is a different matter - I forget what the programme was but I'd watched something minority-interest on the iplayer a while ago and was amused to find that friend T had watched it too). And with on-demand services (whether internet-based or a catch-up TV channel) and the possibility of recording it to watch at a more convenient time, even if you watch the same programme, by the time one person's seen it, the other's forgotten what it was about.
Music is easier to get hold of via the internet, not like the days of browsing through the rock section in HMV and taking your pick, and internet radio means we're beyond the days when you could guarantee that someone would have listened to Tommy Vance because his was about the only rock show available. There's more scope for being able to introduce people to music they might not have come across (that was always a popular way of trying to impress someone as a teenager, as I recall) but not so much of the joy of discovering that the person in your class that you've fancied for ages is also a big fan of (insert your favourite rock band here). Incidentally, even then it's not plain sailing: OneMonkey's happiest with the petulant edginess of The Cure's Three Imaginary Boys, whereas I'm often more inclined to wrap myself in the ribbon-festooned duvet of Bloodflowers.
With multiplex cinemas charging extortionate ticket prices and DVDs getting cheaper, excepting the occasional must-see, even going to the pictures isn't likely to provide a talking-point later at work. And books aren't worth considering in this context.
I've come to the conclusion that the only truly shared experience like the ones Hoggart mentions seems to be the awful reality TV dross. It's so picked-over in the media that if you want to watch, say, some sort of dancing final to get the excitement of seeing who wins, you need to do it within a few hours of it first being on TV, so you and all your friends will at least have watched it on the same evening. And if you want the shared experience without having to go through the pain of watching it, just pick up a tabloid on the way to work and you can join in all the highs and lows, as well as who's hot and who's not. Sharing's not all it's cracked up to be.