I have BT Infinity. I reckon they throttle speeds at busy times although they say they don't. Throttling could be why certain sites are loading slowly for you? Also servers (not that I understand this stuff). I know I use french and South African websites and despite my connection being v fast, they take ages to load or need refreshing constantly.
It's amazing how the capacity of the web expands and copes, with millions of people tweeting their every waking thought. And all those funny cat videos....

I can still remember being shown "the internet" by an academic friend - not all that long ago - and being quite sceptical (Altavista search results being somewhat bizarre!). At that stage , it was designed for academic (and military

) uses.
I still think Wikipedia should get a Nobel Prize though.