Most people are probably safe thanks to the skills of the Muse and (perhaps) their habitat mesh-cleaners. But there are no doubt sites you shouldn't access where you will get more or less stern warnings. Of course, the average person and Muse are pretty wimpy against a dedicated hacker. There are sharks out there, so you better stay in the safe environment of walled gardens provided by your polity/corporation/soviet. As how it is visualised, I think there are *lots* of options. Some just see nice windows, possibly with 3D content. Others want full immersion. Others have visual shorthand that doesn't so much look like anything as just quietly tell them stuff as if they already "know" what is online. Others have their Muse tell them. Everything is skinnable, translatable, can be turned into sound, touch or sonar, mapped onto all sorts of real and virtual objects.