Facebook adds 5 divs, 9 spans and 30 CSS classes to every post in the timeline

Anyone who has written a few scrappers knows how brutally ineffective this is. Yelp tried to pull the same thing and it took me about 3 minutes to rectify my "for fun" scraper. It's also really not that difficult to write a smart scraper that you say, "Look for these things in this post. However you find them, replicate it for the others". Which is ultimately what I made my Yelp scraper do.

If there's a pattern, I will find it, and I will exploit it. <3

That works for a single iteration, but if there are multiple implementations that are randomly chosen when rendered it's a lot harder.

Pretty easy to build a randomizing span algo that you can't hardcode.

Not really. We have scraped many sites successfully that try this randomisation logic. There is always a pattern, which often can be determined via heuristics. It does make things trickier, but not impossible or especially difficult.