Full disclosure: I'm a LOST nerd. No really, I'm that guy. The one who has all the crazy theories about the Island, who Jacob is, etc. I'm going to try to be objective about my appreciation for this show...actually I won't.
For those of you not similarly addicted, here's a brief summary (is that possible?) from Wikipedia:
LOST is an American serial drama television series. It follows the lives of plane crash survivors on a mysterious tropical island, after a commercial passenger jet flying between Sydney, Australia and Los Angeles, United States crashes somewhere in the South Pacific. Each episode typically features a primary storyline on the island as well as a secondary storyline from another point in a character's life, though other time-related plot devices change this formula in later episodes. The pilot episode was first broadcast on September 22, 2004, and since then five full seasons have aired.
When ratings began to drift in season two and early season three and accusations flew that the writers didn't know where the show was going, ABC did something unprecedented. They allowed the writers to set an end date for a successful show.
Now LOST did shed some viewers in the process (in the five seasons, they've gone from 16 million viewers to 11 million). LOST is essentially a niche show on a broadcast channel, yet it has managed to be relatively successful both by critics and viewers. How has it done that? I have no clue. But I have some ideas about why the show still matters:
(1) The writers of LOST, unlike most other broadcast shows, have decided to reward obsessive compulsive viewers like me, while leaving causal viewers in the dust. Some studies have shown that though LOST doesn't have the best ratings during the broadcast hour, it does fabulous online. It's one of the highest recorded shows on DVR, frequently tops iTunes for downloads and tops hulu in views as well. So despite the moves other shows have taken to become more procedural on broadcast, LOST has maintained it's serial nature.