It's not yet directly challenging the likes of Pocket or Instapaper, but Pinterest has taken a step in that direction today. The social networking site has announced that it's begun rolling out a new type of "pin" for articles, which will include things like the headline, author and a short description or excerpt of the article right in the pin (as seen above). Where it differs from other "read it later" services is that it doesn't pull down the entire article for you to read later -- you still need to click through to the original site. As you may recall, this latest move follows an expansion of another sort just last week: an "experiment" with promoted pins. According to the company, Pinterest users should start seeing the new feature on the web immediately, with a rollout to its mobile apps promised soon.