Tumblr's engineering team posts about its infrastructure, including MySQL sharding, PHP 7, notifications, GIF handling and file copying.
HN commenters cite it for a useful MySQL sharding talk, a fast file-copy technique with pigz and netcat, and its PHP 7 move.
It looks interesting but one small thing. I looked into the transferring large files quickly link[1] and saw that they were using netcat and tar to transfer files. This is not necessarily optimal[2], and applying some compression can go a long way, although this will be dependent on the use case. Compression also has the added bonus of transferring less data across the network and (if you don't uncompress) less space at the other end.
SSH is also an option (a slow option, but an option) that provides certain things (encryption, authentication) that make it ideally suited for transfers across network boundaries.
[1] - http://engineering.tumblr.com/post/7658008285/efficiently-copying-files-to-multiple-destinations
[2] - http://www.ndchost.com/wiki/server-administration/netcat-over-ssh
Use gifsicle. It's excellent and very fast, I don't think there's anything that produces smaller gifs than it. [0]
You can also use ImageMagick to produce optimised gifs (it has about 4 different options for that, eg -layers OptimizeTransparency). See [1]. But in my own tests, gifsicle always beats it (often by a huge margin) and is vastly faster. That ImageMagick page may be out of date. Also, Tumblr contracted the author of gifsicle, Dr. Eddie Kohler, to make some improvement for them, hopefully that made it back into gifsicle [2].
[0] https://www.lcdf.org/gifsicle/
[1] http://www.imagemagick.org/Usage/anim_opt/#compress_opt
[2] https://engineering.tumblr.com/post/80003435120/who-doesnt-love-animated-gifs-believe-it-or
Add Tumblr to that list as well. They recently converted their iOS app from essentially pure HTML5 to pure native, which was no easy feat considering the dynamic nature of blog posts on Tumblr, which can contain almost arbitrary HTML content.
http://engineering.tumblr.com/post/35271768127/tumblr-for-iphone-is-now-100-native
Of course, HTML5 proponents will continue to ignore these major data points.
DailyMotion[1] and Tumblr[2] have recently moved to PHP7. In addition, WordPress[3] is moving towards PHP7 as well.
[1] http://engineering.dailymotion.com/php-7-deployment-at-dailymotion/
[2] https://engineering.tumblr.com/post/152998126990/php-7-at-tumblr
[3] (from 2015) https://make.wordpress.org/core/2015/09/10/wordpress-and-php7/
Pretty similar to that, we used pigz and netcat to bring up new MySQL read replicas in a chain at line speeds.
I recall learning the technique from Tumblr's eng blog.
https://engineering.tumblr.com/post/7658008285/efficiently-copying-files-to-multiple-destinations
Slightly OT, but Tumblr gave a great talk about their sharding architecture here: http://engineering.tumblr.com/post/12652551894/slides-from-our-velocity-europe-talk-on-mysql-sharding.
It's really quite a good intro to the subject, I think.