I don't think it's a problem. If everything or most of internet would be somehow preserved, future antropologists would have explonentially more material to go through, which will be impossible. Unless the number of antropologists grows exponentially, similarily how internet does. But then there's a problem, if the amount of antropologists grow exponentially, it's beceause the overall human population grows exponentially. If human population grows exponentially, then also its produced content on internet grows even more exponentialier.

You see, the content on the internet will always grow faster than the discipline of antropology. And it's nothing new - think about all the lost "history" that was not preserved and we don't know about. The good news is that the most important things will be preserved naturally.