Who cares what you're reading?

Several bloggers are debating whether the Kindle and other electronic-book devices are ruining "conspicuous consumption." Kindle user Matt Yglesias laments:

I’m going through Infinite Jest, as are a lot of people this summer, but I can’t visibly display the book on the Metro or around my house.

Conor Clarke translates:

[Yglesias] doesn't get to show the rest of the world that he's reading such a hefty, ponderous tome.

But isn't conspicuous consumption, no matter how banal or useless the products being exhibited, a benign way to encourage human beings to interact with each other? A sizable share of the conversations I've had with strangers on trains and buses, in cafes, and while standing in line for something have been sparked by the reading material in my hand. People see me reading, say, Oliver Sacks's Musicophilia and ask, "How is that?" or "What is that about?" or "Have you read This Is Your Brain on Music?"

I'd say that almost everyone who starts a conversation over a book title is polite and engaging. (People who disapprove of your book generally keep quiet about it.) And many of them wouldn't start a conversation at all without the book as an ice-breaker. Posting your favorite novels on Facebook just isn't the same.