The speed of communication with colleagues around campus, even in other parts across Europe! It's great to be able communicate instantly when you need it most; whether that means being at work or having an exam scheduled during your lunch break (which I often do).
Sometimes there are delays which can cause problems but this doesn't happen very much as far back messages go - so not too many issues here either way really :) Great service overall from janet staff who always reply quickly if they're online/in their office etc., also helpful about how long emails will take before getting them replied after sending off my message!!