The act of writing a long and interesting story with many mysteries, which, due to the story's complexity, attracts many fans, but then continues to stall, prolong, postpone, or flat-out ignores the answers to the story's questions, thus essentially jerking around the loyal fans.
This word comes from the TV show "Lost" on ABC, but can describe any story which follows the definition, such as the the videogame "Half-Life 2", or the manga, "Bleach".
There are two main reasons why a story is "losting". The first is that the writers are not creative enough to come up with an answer to the questions posed that can meet the fans expectations, and thus try to pretend that the questions never existed. The second is that, due to marketing pressures, the writers are forced to continue a story longer than they have ever anticipated, and thus are forbidden from giving away any answers indefinitely. The second method may be referred to as "Milking the Cash-Cow".
A quick way to spot if a story is losting is to look for a situation in which an answer to a story's various questions can simply and easily be answered, only for the story to not do so. Here are a few examples:
After spending an entire season building up the suspense and mystery of the Island's native inhabitants, known as the "Others", one of the survivors of the plane-crash comes face-to-face with an "Other". The survivor asks "Who are you people?", to which the "Other" replies, "It doesn't matter who we are", thus effectively telling all the loyal fans who cared about this storyline to go screw themselves.
In the first Half-Life, you play through the eyes of Gordon Freeman, and thus are purposely not told the answers to many mysteries in order to obtain the illusion that the player is just as confused as anyone else is in the story after an alien-invasion takes place.
However, ten years later, during Half-Life 2, you are surrounded by dozens of friendly characters who all know exactly what happened during the events of the first Half-Life. Despite this, no answers are given, leaving fans to read separate books and searching for hidden audio files within the games to fill in the blanks to the story.