Fastmail has one of the few interfaces that gets infinite scrolling /right/. The outer mailbox div has overflow-y: auto; and the inner div is the combined height of every message in that folder -- my inbox has 11381 messages, and the height is 364192px. When the scrollbar is moved, JS automatically determines which messages to load. Messages themselves are tiny AJAX requests that take less than 100ms each.
This is from the perspective of using Chrome on high end hardware, but I couldn't ask for a better web interface.
That said, they aren't joking about needing a new mobile interface: the current one is usable, but definitely lacks the same polish as the desktop version.
I agree. The infinite scroll is really well-implemented in FastMail. It's much better than the pagination in Gmail, which makes it extremely difficult to jump, say, 2/3 of the way down in a search or label with thousands of hits.
This is from the perspective of using Chrome on high end hardware, but I couldn't ask for a better web interface.
That said, they aren't joking about needing a new mobile interface: the current one is usable, but definitely lacks the same polish as the desktop version.