"Ping an article" refers to bringing the article to someone's attention by replying to the article and including that person's name in the "reply to" box. You can also ping (or flag) an article to a special interest list by typing the name of the list in the box. FR special interest (or bump) lists are located here. People interested in a specific topic can then search all articles posted that are pertinent to that topic and properly flagged. Individuals can use the "Self Search" feature to locate articles where other members have pinged/flagged them. Also, by "bumping" an article, you effectively flag yourself since your replies will also show up on a self search. The whole process makes navigating FR easier. Hope that helps. :)