Mobile phone technology has affected dramaturgy. It is now less likely that someone who finds themself sharing their house with a killer will not be able to get to the phone. Surely they can just reach into their pocket? Thankfully, loss of battery power and failing reception can still come to the rescue, so to speak - but there is a difference, and possibly a thematically significant one, between being cut off from contact with the outside world by a malevolent force on the one hand and failings of technology on the other.
I used my mobile phone at work today to text my good friend James MacDowell to pose an open, film-related question, as I often do. 'Can you think of instances where characters in fictions use internet search engines'. The first one that sprang to my mind was actually from a novel: in George Pelecanos's The Turnaround, a character goes on the internet to research an old local news event. James replied that the old trope in horror movies of characters going to an old dusty library to find out a key piece of plot information appears to be being replaced by them looking on the internet.
As is so often the case with film studies questions, it pays to start with Hitchcock. James's mention of the library made me think of the scene in Shadow of a Doubt where Young Charlie (Teresa Wright) runs across town to the local library - catching the stern, spinsterish librarian just in time, after being reprimanded by the traffic cop for stepping out in front of a car - to read the news of the 'Merry Widow Murderer', putting together a few other things she knows and deducing that it is her beloved Uncle Charlie (Joseph Cotten). Following this revelation, as a shocked Charlie walks numbly across the library floor, Hitchcock's camera executes a rhetorical flourish, moving up and away from Charlie and taking up 'the high angle of knowledge' (is this William Rothman's term?).
If we were in the twenty-first century and not the 1940s, Charlie would not have to interact with the members of her local community or worry about closing times (much as the contemporary television viewer does not need to worry about getting home in time for their favourite series, and therefore does not necessarily watch it at the same time as everyone else, thus feeling part of a communal experience). She wouldn't have to leave her laptop in her bedroom, thus precluding the social encounters and spatial possibilities that are so readily available to Hitchcock.
As James also pointed out to me, the bookshop scene in Vertigo would probably have to go too, at which point I ceased to be able to think analytically, and could only reply with 'Nooo!' (a response that James admitted was also the way he had thought of ending his previous message). Perhaps Pop Leibel and google are interchangeable to Vladimir Propp, but they are not to me.