Sure, but it's always more tempting to do so, if I can get the gist of what overall point the author is trying to make, in the posted excerpt.
Many of us visit dozens and dozens of individual threads per day. If the original articles are well excerpted, one can often grasp the most salient points without having to go to the link and dig them out - thus conversation can ensue post haste.
That's all.
Free, Reader’s Digest Republic?