r/Place was a collaborative drawing board on Reddit in 2017 April Fools' Day
How Reddit built the backend, API, frontend, scaling, caching, handling
bots, etc.
Collection of blogs from Figma about their real-time editing and multiplayer
A good dive into how Figma built real-time editing and multiplayer
application
There is a specific label called author_is_elon
(ref)
Jack Dorsey, Katy Perry, Stephen Curry and Barack Obama are labelled as
testing accounts
(ref), which
is now overridden by a forced push
(ref,
original commit)
Designing systems at the scale of S3 means 1 in a billion might be a daily
occurrence
From the physical hard disk storage to managing heat (load balancing), to
data replication, to data placement
There are also considerations of human factors, e.g. threat model and
lightweight formal verification
The last bit is inspiring, scaling the team is as important as scaling the
technology. Encouraging ownership intrinsically motivates people to push
forward. As a senior engineer develop and articulate problems, rather than
pitching solutions.
Using accelerometer data, convert it to vibration frequency, train a model
to determine whether it's a train ride or not, mix data with train schedule,
last known GPS and time since then to estimate location