How will people in the future look back on today? Welcome to The Philosophy Forum.
Studying history is actually a pretty good way to make the people and societies of the past, even 100 years ago, (understandable and "alive".
The people and society of 1900 are accessible, "relatable", and understandable, provided one makes a little effort. After all, 1900 isn't ancient history. Yes, society has changed--it's always changing--but there are many constants which haven't changed.
Your assumption that people in 2118 will have a clear picture of 2018 because of the internet, recordings, films, videos, photographs, and so forth is not altogether well founded. We do not know how much of current communication technology will be operable, accessible, or even in existence in 100 years. Already, technology of the 1960s, like 2" wide video tape is largely lost because the technology was abandoned. The internet will be as enduring as all the big server farms scattered around the world. Do you think the millions of digital machines sitting in the big windowless buildings are still going to be working in 100 years? 25 years? It isn't certain whether CDs will still be playable in 50 years, assuming one still has a CD player.
The media that are most enduring are physical media: film, vinyl disks, print on paper. Virtual or digital media depends entirely on technical continuity over multiple decades of time, something we haven't seen so far.
If libraries keep collections of books, magazines, newspapers, photographs, vinyl recordings, or somehow maintain stocks of machines and servers to preserve digital information, then a record of today's society will be available in 2118 and 2018 will be understandable and accessible. Some libraries have already dumped their newspaper collections -- not because they were unusable, but because the librarians decided the future was in microfilm and digital storage.
Is the society of 1903 Boston in this silent film of 1903 so strange? Electric street cars, crowds, bad traffic...