Headlines in newspapers and magazines were once written with readers in mind, to be clever or catchy or evocative. Now headlines are just there to get the search engines to notice. In that context, “Jon Stewart Slams Glenn Beck” is the beau ideal of great headline writing. And both Twitter and Facebook have become republishers, with readers on the hunt for links with nice, tidy headlines crammed full of hot names to share with their respective audiences.

Keep in mind that all of the things that make headlines meaningful in print — photographs, placement and context — are nowhere in sight on the Web. Headlines have become, as Gabriel Snyder, the recently appointed executive editor of Newsweek.com, “naked little creatures that have to go out into the world to stand and fight on their own.”

Some of them are a little more naked than others.

“Taylor Momsen Goes Pantsless, Curses on Morning Television” suggested a headline on The Huffington Post’s “most popular” feature on Friday. She didn’t actually appear bottomless, but that’s part of the trick of writing digitally snappy headlines. It seems almost tasteful next to an MSN take: “Taylor Momsen Vomits On-Stage, Wants to Be Kurt Cobain.”

The Huffington Post knows its way around search engine optimization, or S.E.O. as it’s known. A story about whether the president would play golf with Rush Limbaugh was headlined: “Obama Rejects Rush Limbaugh Golf Match: Rush ‘Can Play With Himself.’ ” It’s digital nirvana: two highly searched proper nouns followed by a smutty entendre, a headline that both the red and the blue may be compelled to click, and the readers of the site can have a laugh while the headline delivers great visibility out on the Web.

The Huffington Post sometimes tests two different headlines in real time to see which the audience is responding to. (“How to Reduce Your Oil Footprint” did better than “How to Say No to Big Oil and Reduce Your Oil Footprint.” Go figure.) The site also uses its Twitter account to solicit reader suggestions on headlines. Arianna Huffington, editor in chief and a founder of the site, rejects any notion that it is dumbing down in search of eyeballs.