Has anyone ever looked inside Fakebook. OK they must have Terabytes of PHP &/or bespoke other software, but they still feel the need to bloat your page with 180 JavaScript files. All loaded with crap to obfuscate reverse engineering. And 180 is without addons for Fakebook.

Now why would Fakebook do that? Could it be a prime example of distributed computing? A billion users would require a humongous allocation of resources when you could off-load to the billion PCs sitting doing practically zilch most of the time.

Screen size, text size. Checking arrival & full rendering etc. Ya cain't do that server-side, only the PC you are looking at knows how slow, how big, how tied-up with other tasks it is, so JavaScript is your answer!

& I would bet Fakebook has some fancy encoding (eg images) that JavaScript unbundles to limit the size of transmitted packets.