Friends exists in that time period just before social media - ending the same year that Facebook was founded. Because of this, the characters may occasionally reference email (like when Phoebe asks for people who want to receive emails about performances to give her money to buy a computer), and no one can forget Chandler's 'top of the line' computer (that is now hilariously outdated). However, the lack of social media and smartphones also created some situations that simply wouldn't happen today.
From the many (many) voicemail related episodes to the character's financial situations, social media and smartphones would have changed pretty much everything in Friends... except, of course, whether or not Ross and Rachel were really on a break.
Chandler & Janice Meeting Online
Chandler and Janice have a long history of breaking up and making up, and one of the most significant times that they actually date on the show is after they reconnect online, without knowing who the other person is. It's a sweet little storyline, as they have digital dates and communicate purely through chat, but never actually see each other's face. These days, though, Chandler would have been looking on Tinder, not chat rooms, and would have immediately known who Janice was (and swiped away).
Rachel's Drunk Voicemail
One of Rachel's worst - but funniest - first dates is when she goes out with someone new right after learning that Ross and Julie are going to get a cat together. She's so upset at the news that she gets drunk and derails the date, eventually grabbing a stranger's phone and leaving a message to tell Ross that she is 'over him' and that is 'closure'. Ross doesn't end up actually checking his voicemail until the next day, when Rachel remembers and tries to prevent him - something that wouldn't have happened if he had a cellphone. If that was the case, he would have listened to the drunk dial immediately - or even picked up!
Monica Breaking Into Richard's Voicemail
Another major voicemail-related moment is when Monica attempts to leave a 'breezy' voicemail for Richard that actually ends with her saying 'I'm breezy' out loud! She knows Richard's voicemail code, and so dials in to play it back for the rest of the gang, then tries to delete it, freaks out over a different message from a woman, and ends up recording a new outgoing message that is spectacularly embarrassing. Of course, none of this would happen, now, as dialing into a voicemail from another landline phone just... isn't a thing. She may have panicked seeing Richard post with another woman on social media, though, and sent some embarrassing posts herself.
Rachel Could Have Had An Influencer Career
If there is one of the gang who would have been phenomenally good with social media, it would have been Rachel. She manages to work her way up in the world of fashion through sheer hard work and talent, but in a social media world, she probably wouldn't have done any of it.
Instead, she would have become an influencer, and run a fashion blog, YouTube channel, and Instagram account - and probably been incredibly good at it, too.
Chandler & Bob
In yet another voicemail-focused episode, Chandler ends up meeting a woman through a voicemail left at a wrong number. She leaves a message on his machine looking for 'Bob', he pretends to be Bob to set up a date, and then comforts her when 'Bob' stands her up. It's not his best moment in the show, for one thing, but beyond that, it just wouldn't happen with social media. She would have just looked up Bob online, rather than leaving a message at an old number, and Chandler wouldn't have got involved.
Rachel & Monica Couldn't Pretend To Be Each Other
In one of the earlier episodes, Rachel ends up injured, but has to pretend to be Monica in order to use her health insurance. Then, when they meet two cute doctors at the hospital, they decide to maintain the ruse on a double date - and of course, it all goes horribly wrong. With social media, though, this would be difficult. They may get away with the initial insurance fraud, but the doctors would undoubtedly look them up on social media before the date, and quickly see that they aren't who they say they are.
Mike Intercepting Voicemails For Rachel
One of the later episodes includes a particularly funny dynamic as Mike overstays his welcome at Ross's place in order to do a favor for Rachel - who has given out 'her' number to a cute guy at a bar, and then realized that it was a shared phone with Ross (who she lives with), and she doesn't know how Ross will react.
Mike sticks around in order to awkwardly run interference, answering Ross's phone for him until Rachel gets home. It's a great scene, and shows just how great Mike is, but would never happen in a world without landlines. Rachel would just have given the guy her own number, or her social media handle.
Monica Would Be Obsessed With Pinterest
Some might assume that Monica would be a food blogger, but she doesn't exactly take criticism well, and would probably struggle to deal with the comment sections. However, she would definitely be obsessed with Pinterest. She loves being the hostess and keeping things organized, and the site would make her incredibly happy - possibly leading to an episode about becoming a little too into it.
Joey Would Have Some Kind Of Social Scandal
Joey proves in the original series that while he may love being famous, he's not always the smartest when it comes to how he handles fame. In the series, he ends up written off Days of Our Lives after claiming in an interview that he wrote a lot of his own lines - and nearly messing up a second time, after he is back on the show and doing another interview! This, combined with his lack of common sense would undoubtedly lead to some kind of social media scandal for the soap opera star.
Smelly Cat Would Go Viral
In the series, Phoebe is trying to make a name for herself as a musician by playing gigs in Central Perk and occasionally busking on the street, and that's about it. Unsurprisingly, she doesn't end up wildly successful as a musician, but even so, she has a couple of brushes with fame courtesy of Smelly Cat. If she had access to social media, though, she would definitely become a viral star. Her quirky songs would be a huge hit online, and her personality would have fans flocking to follow her.