When in doubt, use the real-world for a guideline. In this case, road signs provide a perfect metaphor. In the case of street signs, arrows pointing to the right are always positioned after the text and arrows pointing to the left are positioned before the text. In the case of links, these little chevrons or triangles almost always point to the right so it's natural to position them after the link text.
I have a site that's "You have done blah. Want to return to previous blah?" Now where do I put that previous arrow?
(Its made more annoying because I have lots of parallel "You are viewing an old version. Check out the newest version >>", so we want to stick an arrow in for visual similarity... but its confusing.)
Sorry I must have explained things poorly. There are lots of little blurbs "X happened, would you like to go look?". Sometimes that go look is a backwards motion and sometimes its forward. "X happened, « would you like to go back" looks really strange.
Not a very authoritative usability article in my book. It's just the intuition of some random guy as far as I know. The arguments are scarce and there are no usability studies to back it up.
Intriguingly, I had no opinion on this before going to that page, but after looking at their examples, something about the "arrow after" examples make me want to click on them more. It's only an anecdotal data point, but others comment similarly.
