Problem: The time people have to translate is limited, therefore it might be feasible to dispaly the number of "hits" an article gets in the source language. Articles that get many hits may be more feasiblefor translation
Proposed solution: When displaying proposals/suggestions for translations, also display the number of pageviews, and perhaps make the list sortable by this field. The idea is that articles that get many hits in the source language, might also get many hits in the target language.