"Lurker" is the term used for someone who regularly reads a blog, but never comments. According to Wikipedia, the term dates back to the mid-1980s, when most people did not have access to the Internet, but used BBS chat rooms and message boards instead.
Because BBSs were often accessed by a single phone line there was an expectation that all who used a bulletin board would contribute by uploading files and posting comments. Lurkers were viewed negatively if they did not contribute but kept the phone line tied up. Sometimes newbies to Internet communities are asked to "lurk" to get a feel for the vibe. The verb to "de-lurk" means to start contributing actively to a community having been a lurker previously.
According to my Google Analytics stats, there is an awful lot of traffic on this blog, but only a few post comments. So, I thought I'd issue an invitation for lurkers to decloak. The topic for the lurkers to chime in on is an easy one...let us know what you think the worst song of all time is.
My vote goes strongly to "She's Having my Baby" by Paul Anka. (Makes me want to put a spoon through my ear.)
On your mark, get set, comment!