Why is a "recommendation" bar shown with some articles?

After reading an article, ProZ.com members are presented with a form allowing them to recommend whether other translators should take the time to read that article. The recommendation bar shown with an article is an average of all members' recommendations. 5 bars indicates members thought the article was well worth reading, while 1 bar indicates that members definitely would not recommend the article to others.

The most highly recommended articles are shown in the "recommended articles" section of the right sidebar.