A few things come to mind when considering the idea of the internet in the 40k universe.
1. I highly doubt that the Imperium would wish for its subjects to have access to unfiltered information.
2. On tech-rich planets there would likely be communication and computing networks, but such things would likely be highly restricted and secure.
3. The internet would be a prime breeding ground for heresy, or worse actual chaos taint. The ruinous powers love to use humanity's technology against it.
In other words, no there would be no such thing as the internet on any Imperial world. In fact, thinking about it, I'm pretty sure such things would be proscribed by law. It's far too dangerous.

