Some players that you personally may not have met before may have a massive amount of ingame knowledge that you don't have, and providing basic information to them when misunderstanding their question or their need for an answer is going to be at best a waste of your time and at worst come across as patronising and offensive. Equally giving a high level answer to someone who is new to the game may well be confusing.
Sometimes this is unavoidable, but a few simple questions and a tiny bit of research on your part will help to target your replies more quickly.
To see how long a player has been ingame look at the player profile, at their employment history. Scroll down and look at the first date mentioned, This is when they came into the game. You can also look at security status and standings to see if thay have actually been active in that time (remember strongly negative security status is as much of an indication of activity as positive).
If someone has been in the game a while and is asking an apparently simple questions, or hasn't done something you think is obvious, try a short, pithy reminder. If that doesn't work and they express some further lack of understanding by all means launch into a full explanation, perhaps questioning if they have been out of the game a while to get to know them better.