Someone invented the Internet more than a hundred years ago
It didn't work out because of the technical problems. It was called the Mundaneum. With powerful enough analog computers, digital counterparts of the like Charles Babbage had already designed, and monied backing neither Charles Babbage nor Paul Otlet ever had, you could potentially engineer and build custom analog computers that would run the Mundaneum.
The Mundaneum is simply a physical location that is an analogue to the ephemeral location we call the Internet. Its basic functions are essentially identical. With the Internet, I type "difference between dreadnought and parlour guitar", the request is sent into the workings of the search engine, whose automated algorithms return what (I desperately hope) are relevant documents, images, and videos that relate to my question. With the Mundaneum, I send a telegramme to their central receiving office who would then translate my request into the relevant catalogueing scheme, a research team would, using their own algorithms, research patents & makers & catalogues of musical instruments. They might write a short, well referenced report and telegraph that back to me. I don't know if visual data can be sent over telegraph systems, but they could easily mail a microphotograph of the pertinent visual data, along with their written report, which I would then have blown up to its original size.
While it is true that the Internet is a communications network, it is also more than just that. It is also true that the telegraph system through which the real world Mundaneum would have done its work is a communications network. The real world Mundaneum is simply the "cloud storage" part of the fictional world Internet. While the relays and wires and people sending the telegrammes are the "communications network" part of the fictional world Internet.
What is the Internet, exactly?
What makes the Internet different than television? Or radio? Or the printing press, or the mail? The Internet is:
- A way to transmit information
- That allows any node in the network to send messages to any other
- In real time
- And the contents of said messages can contain arbitrary data
Television is an audiovisual feed only; radio is audio only. Both are single-source many-receiver. Telephones let anyone talk to anyone; but that specifically means only talking. The mail isn't real time.
The Internet can do the job all these things did, and more. That's why the Internet is replacing them all. Already many "landline telephones" behind the scenes are transmitting calls over the internet.
But there's another layer built on top
The internet technically existed in the late 90's. It was nothing like what we have today. But what we have today is nothing more than a few extras layered on top of "the internet":
- The web is basically a collection of 'documents' your web browser knows how to display, containing 'links' it can automatically follow.
- Organizations began using this technology as an interface to build and design ever more complex services.
You can think of any given website as a really big encyclopedia. A URL is just a page number. When you go to the site, you send the site's bank of servers a request. The site's computers go find the document for you, and send it back.
Nowadays, of course, the documents are actually generated on the fly; when you go to hotels.com and search in the search box, their computers receive the request, decipher it, look up the relevant info in their databases, then craft a reply. Google doesn't precompute search results for every search into an enormous encyclopedia; it has a queryable database, it runs your search, it spits out an answer.
What Paul Otlet invented
Paul Otlet invented Wikipedia in 1910. He called it the Mundaneum. He couldn't actually build it, of course, but oh how he tried. For decades, he tried. But like Charles Babbage, his idea was simply so far ahead of its time he just couldn't make it happen.
He anticipated having a network of "electric telescopes" (computers) that could all talk to each other. That's basically the Internet. He anticipated using links to connect the documents into a giant interconnected web.
What could be done without electronic computers
Charles Babbage already had a design for the Difference Engine. His technology doesn't use transistors. It isn't even electric. We know that it works, if only you can build one, because in 1991 someone did. The Computer History Museum in Mountain View has another it uses for demonstrations.
Charles Babbage designed what is, for all intents and purposes, a machine computer. He just was never able to get the money or resources to build such a ludicrously intricate piece of machinery. But his Analytical Engine was indeed a bona fide computer.
In your world, transistors simply don't work. Analytical Engines will. They'll never be anything like as powerful or as cheap to operate as electrical computers were even in the 80s.
Hook Babbage and Otlet up with deep pockets
If Babbage had successfully been able to make the Analytical Engine a reality, then by the time Otlet comes into the picture, what we would call a modem might have existed: Imagine duct taping a telegraph to an Analytical Engine.
In which case, Otlet's grandiose vision can actually be realized. The Mundaneum comes to be a thing. In order to use it, you have to be at a place that has a connection to a telegraph line and an analytical engine. But that's still a pretty big change; libraries and other place (like very up-scale hotels) will want one.
In turn, others will eventually start offering their own special services that you can '[tele]graph into'. Said hotels will already have most of the equipment, so it's just a matter of hiring an Analytical Engineer to make the machine automatically respond to telegrams inquiring about reserving a room, or checking on the status of an existing reservation. Banks will find having access to an information sharing network very lucrative, so they'll want in as well.