Would you answer this user's questions only because you know them?
In theory, that could be a useful strategy. For lengthy periods of time, I mainly answered (and occasionally asked) on the java tag on stackoverflow. Thing is: that "place" is swamped with all kinds of "bad" questions. Either badly written, so you have no idea what is asked, or the zero-prior-research 1 millionth repetition of "I got a NullPointerException", or "here is my homework assignment" requests.
When you thus come to that "place", to learn something, and maybe answer interesting questions, then of course, it would seem reasonable to check if some person-you-know-to-ask-good questions put up a new question worth looking at.
But in practical reality, it doesn't work that way, at least for me. Because those people that write good questions, they don't do that "often enough". When your goal is to provide good answers, and to acquire +X reputation over the next Y days, then you don't wait for some "friend" to drop a new question. You dig through the mud, hoping to spot something worth your time, no matter who wrote it.
Beyond that, I personally made these experiences:
- Sometimes you help a newbie, and then a few days later, you come across another nice question of that person. And so on. And that just feels great: you can see how that person makes progress over time, and really cool: you can see your own contribution to that.
- When other "experts" ask questions, most likely: their questions are hard. They are experts already, so there is a good chance that I can't answer their questions. At least not immediately, and without spending some serious amount of time and energy.
Taking these things together: "knowing" people is "nice", as it allows to "connect" to people beyond pure technical content. But it is not something that affects my selection of questions.
Finally: at least in my perception, "fame" (at least on stackoverflow) comes out of writing great answers. I couldn't name a single user there who is known throughout the network for mainly/only asking great questions. When you look at those 8 users that are above 800K reputation on stackoverflow right now, the max number of questions asked is with commonsware, who has 114 questions. And Gordon, with the most answers (62K!!!) ... 0 questions asked.
As said: "fame" is about writing many great answers, not questions.