I haven't read Tim LaHaye and Jerry Jenkins' Left Behind series of apocalyptic novels, but I have a good idea of the plot and themes from reading the analysis of the series on Slacktivist's blog. I don't share the theology and worldview of the series anymore, but I'm intimately familiar with it because I was a dispensational premillenialist until I was 25 or so (in other words, I believed the world would end much as the Left Behind books portray it).
In Rapture Culture: Left Behind in Evangelical America (Amy Johnson Frykholm, 2004), the author, who, like me, grew up in the subculture but has since, um, left it behind, interviews an assortment of readers to get an idea of what the books mean to them. There's been plenty of analysis of the books' literary merit or lack thereof, their politics, the way they treat gender, etc., but less on what they mean to the people who choose to read them for pleasure and/or edification. And Frykholm's main point seems to be that their meaning isn't as monolithic as outside observers might think--that these readers, like any others, bring their own lives and meanings to the texts and are capable of accepting or rejecting what they read as free agents. She also talks a lot about the meaning of community for Left Behind readers, both in the way the books have been popularized through word-of-mouth marketing in churches and families and in how readers tend to especially admire the books' Tribulation Force as a sort of ideal community to aspire to.
I'd be interested in similar studies of reader interaction through book clubs, Oprah books, internet communities, and the like.