Supposing the game has knowledge-type skills: When players are curious about something or encounter something they might know, first tell them whatever immediately springs to mind about the subject and then have them roll the knowledge skill. They can ask one question per level of success (or in case of D&D, maybe one question per 5 or 10 points in the result or exceeding the DC or whatever). Answer the question if possible, and if not, let them ask another one in place of it.
This relies on setting a price to the knowledge, which makes it feel more valuable. (Compare: People are more likely to play a game they have bought or extensively searched for than one they happened to encounter for free on the internet.) Also, the players get to ask whatever they don't yet know and what they feel is important. Also, if they roll well and get many questions, then they are likely to want to use them all, which lets you communicate even more setting info.
For example: "What is Mournland?"
A: "It's this magical wasteland in Khorhaive where bodies don't rot."
Then the players get to ask questions, like maybe they wanted to know how far away it is, is there treasure there, does anyone live there or why would anyone go there.
Another example: Do goblins have a written language?
A: Well, off-hand you do know the goblins have a sovereign state (and whatever their reputation in Eberron happens to be).
Possible questions: So, do they have a written language? How many are literate? Do they all share a common language? Is it specific to goblins or do humans speak and write the same one?
With reasonable level D&D 3, I'd go with one question if the check is at least 5, 2 if the result is 10, 3 if it is 15, and so on. 3 questions is probably what you want skilled characters to often achieve, so adjust the numbers as necessary.