One of the things that each quest has is a short story. There are the main characters (or items), the interaction between them, and the sequence of events instigated by them that eventually lead to the completion of the quest. But then the story ends, the cake is made, the favours are done, and the enemy is defeated.
And then what? Normally, a book is put away and the DVD put back in its case. Simply put, the end. But unlike books or movies, characters continue to exist and interact in the world of RuneScape. The play is over, but the curtain never falls.
It's interesting to interact with characters afterwards. With Jagex updating the game regularly, you never know if your favourite NPC will feature in yet another story, and more often than not, the NPC will have some "additional information", as sort of an epilogue.
We've seen a few times that NPCs have been recycled (and done so rather well) throughout a few quests, and more often than not have elements of previous quests proven to be the key in solving the mystery.
But storylines that span multiple quests are by far the most interesting, if not too few. For instance, the Desert, Plague and Fremennik quest series have no distinctive storyline in them, but quest series like those of the Myreque or Goblin vs. H.A.M. are like chapters of the same book. The difference is kind of like those 80s TV shows compared with whole movie series of today; what MacGyver did in one episode had no effect on any other episode, but you cannot watch Harry Potter movies in a random order.
There are some quests that are no series, don't have a story line that connects them, but are still connected. Think back when you first heard of the Mahjarrat, and then the quests in which they featured. Only recently with the unofficial release of Mysteries of the Mahjarrat have those Mahjarrat based quests started to interconnect with one another. Another example is of course Recipe for Disaster, where numerous and high level quests suddenly connected with the simplest of quests around. And how about them Slugs? I think I saw one burrowing in the brain of a Penguin Admiral.
And what about quests that connect with one another only because they have something in common? Recently we had retrieved Arrav's heart, but before that we helped Cyrisus find his courage, and assisted a bunch of monks with finding their brains. Anyone else see a yellow brick road coming down the line? Click your heels three times if you agree.
We know of a few storylines that will be resolved sooner or later. Lucien is close to achieving Godhood, a whole bunch of other Mahjarrat are getting antsy about an upcoming ritual that is very important to their survival, the Dwarvish Red Axe faction is rumoured to make another move, Arposandra and Prifddinas are still inaccessible, and we have yet to stop the tragedy unfolding in Morytania.
But even then, what other tricks are up the rolled-up sleeves of the creative writers at Jagex? For example, I would not put it past them to mount Dwarven Cannons on Giant Gnome Tortoises. I'm personally hoping for a quest that you can actually fail at, rather then attempt it dozens of times. Too bad, you didn't stop Lucien, now suffer the consequences.
But they have come a long way from single, short (and illogical) stories and actually managed to write down a coherent and logical history of RuneScape and the people living in it. And I think that this has been the most important step. You cannot know where things are going, if you do not know where they have been.