According to Wikipedia, you are referring to the points of the compass:
The points of the compass are points on a compass, specifically on the compass rose, marking divisions of the four cardinal directions: North, South, East, West. The number of points may be only the 4 cardinal points, or the 8 principal points adding the intercardinal (or ordinal) directions northeast (NE), southeast (SE), southwest (SW), and northwest (NW). In meteorological usage further intermediate points are added to give the sixteen points of a wind compass.[1] Finally, at the most complete in European tradition, are found the full thirty-two points of the mariner's compass. In ancient China 24 points of the compass were used.
(emphasis mine)
New and Improved; Made-Up Definitions:
Altruistic Vampire -one who subsists on the dopamine released when they help another; for whatever personal motivation: an addict of altruism; someone addicted to answering questions online. -Similar and often found in conjunction, though not to be confused with: Stack Exchange; Rep-Whore.
Cyber Vampire -one who subsists on the dopamine released when they telecommunicate with other people; someone addicted to interpersonal relations which can only be found online.
Until I looked it up, this is what I thought Help Vampire meant (apparently it means ne'er-do-well).
Any 'new' word is just window dressing for the word addict. Like this 5yo question that seems to be getting along just fine: How addicted to Stack Overflow are you?.
Internet traffic tracking sites have a category for addicts. IIRC, of the two SE sites that are on the top 100 list, ~50% of its users are addicts. I hope I can safely make the assumption that way more of that 50% are altruistic than help. Therefor I just call myself them (for good or evil) a
Stack Exchange Addict.
For a definitive answer we'd need to know why they're addicted; are they a rep whore or one of the two vampires? We need more information to narrow down this obsession. However once we have it, we no longer need this mysterious all encompassing word for "someone who is addicted to a Q&A website".
Although fitting, I believe it would be a stretch to call them trolls. It would be immediately misunderstood; crossing this bridge requires you to read my answer to your question.
We're all trolls. It just depends on which side of the Schwartz you're on; the Up side or the Down side.
Best Answer
Since the question does not specify that the person actually be helpful, just someone who is stopped to ask a question of, they could be a "bystander":
or more specifically to your question, assuming whomever it is you stopped was on foot, they can be a "pedestrian"
or a "pedestrian bystander" :-)