Developer

GitHub
Built for developers
Bootlin
Elixir Cross Referencer
Kernel
Linux Kernel Archives
NGINX
High Performance Web Server

Discussion

Reddit
Social news aggregation
HostLoc
Hosting forum
V2EX
Way to explore
SegmentFault
Learn skills, solve issue

Utilities

Compressor
Optimize images
Convertio
File Converter
FreeWWW
Lookup toolset
Tool.lu
All-inclusive

Privacy

IP check
Anonymity testing
Whoer
Disguise testing
IP leak
IP leak testing
DNS leak
DNS leak testing

Travel

ExploreMetro
Metro maps
Moovit
Urban mobility
Mastercard
Currency Converter
OANDA
Currency Converter