It's definitely done to obfuscate as well - I took a look a while back and they were intentionally splitting up things like the "Sponsored" text into tons of tags and gunk to make it harder to find programmatically.
I'm sure it is possible they are doing it as well, but I was talking about what I saw on twitter's new design. I don't use Facebook, so it was definitely Twitter I saw. This was a while back, so potentially it isn't the case any more.