I try not to post entire articles because doing so can jeopardize FR by exposing it to copyright violations. Besides, the site of origin deserves the hits and the revenue. Instead, I excerpt them. When excerpting an article, I look for an eye-catching quote that will get the reader to read the entire article.
Standard procedure is to give the beginning of the article and let readers decide if they want to read the rest. Picking sensational quotes out of context doesn't give a clear idea of what the author's argument is. When you realize that a lot of the people writing back are posting on the basis of your excerpt, not of the actual article, it's all the more important not to skew things by picking the most controversial quotes.