Eminem's "Stan" depicts a dark side of the culture industry: parasocial relationships. Since "Stan" was released in 2000, we can use it to compare how changing communication media have changed the nature of parasocial relationships.
In 2000, when Eminem released "Stan," music was still often consumed using physical media, such as CDs. This makes the speaker, Stan's appreciation of Eminem's earlier music even more impressive — it wasn't like Stan could have just found them on YouTube.
More importantly, the communication media that Stan uses to communicate with Eminem are in-person (waiting in line for an autograph), phone calls and physical letters. While phone calls left immediate records of their use in the form of voicemails, the other two media do not have any equivalent notification of receipt. If a letter gets lost, there's no way for the intended recipient to know where it went, until they find it.
Conversely, digital communication media now (email, IM, social media post or DM) allows for immediate proof that a message has been sent (and confirmation whether it's been viewed), and means of easily searching inboxes for received messages. And some platforms have bots that can detect harmful or threatening language and flag it.
The speed and responsiveness of these forms of communication media mean that parasocial relationships can now be performed more efficiently, with celebrities granting contact to their fans in small ways, such as liking their Tweets or tagging them in pictures. This could mean that more harmful parasocial relationships form. However, a situation like that in Stan could be less likely:
Perhaps Stan would instead post their threats publicly, a response to which could lead to quicker intervention by Eminem
The ability to respond to fans more quickly (and potentially with the use of staff or automated tools) could have lead Eminem to have a quicker response, and prevent Stan from hating him in the first place
Since it's easier to quickly parse the content of DMs than voicemails or emails, Eminem could have potentially seen Stan's threats faster and intervened sooner
I feel like I'm implying that the fictional Eminem was responsible for the murder in "Stan." I'm not — rather that the "Stan" plot seems less likely with today's forms of parasocial relationships, which, like much digital communication, are more seamless and responsive to the sender.