How it held up
Everyone watching the results loaded the same two small files, one for the count and one for the exit poll, straight from the CDN, which kept a copy for two seconds at a time. A crowd refreshing at once never reached the database, which is why almost every request was answered without running any server code. Server code ran only for exit-poll answers, noticeboard posts and the volunteers entering counts.
The firewall's rate limits applied only to things people sent in, never to viewers, so a whole hostel watching on one Wi-Fi connection was fine. Across the day the firewall blocked 552 requests, and the server code returned an error just once.
The count
Counting ran from 15:26 to 17:43. Two volunteers typed in 42 count updates as figures were read out, and each post was declared once its count finished.
The exit poll
191 people answered. Of the 16 seats with enough answers to call, the poll's front-runner won 14. Posts with too few answers were never shown, and the poll was only ever whoever chose to answer, not a scientific sample. See the comparison post by post.
Afterwards
The live site was shut down after the election. Its servers and everything stored on them were deleted, and this static archive replaced it. See Privacy, and the source code.