The only reliable measure of whether a piece is any good is visitors - are people reading it, is Google featuring it in their search engine, are people sharing it on reddit? If you use an analytics package like Google analytics, which filters out all the bot hits and only counts the views from a browser, you can get a pretty reliable idea of which articles are popular.
I would prefer some mix of these measurements. It would be great to motivate authors to create quality content that someone will really read/use/need. Rather than pages with funny pictures that are attracting visitors
.