Websites used to have links pages. I've been online since 1992 when search engines were many but it was a young technology. An important part of finding one's way around was relying on the curation of sites worth visiting. I want to bring that back.
Digg - An old favourite. Always something interesting.
Cool Tools - I'm a bit of a tool collector, and this site is always surfacing interesting ones. It also highlights interesting services and software.
Lifehacker - Don't bother with the UK version, it's just a watered down copy of the US version. I particularly enjoy their new Weekly Upgrade posts.
Make Use Of - Similar to Lifehacker, a good mix.
How-To Geek - More computing focused than Lifehacker and Make Use Of.
BoingBoing - The original blog. Been around forever. More contributors than they used to have, but still unearths some gems.
Adam Nash Photography - A fine photographer.
Derek Sivers - One switched-on cookie!
Images Guide - Andy Osmani's guide to essential image optimisation.
Unsplash - This has become THE source for free images, for any use and any reason. They don't even require attribution. It's a stunning resource. I've got a few pictures on there myself.
Workflowy - A very elegant Todo app.
Thingiverse - As good as other sites are, this has to be my first port of call.
Pinshape - Excellent quality models.
Image to lithoplane - Neat tool to create lithoplanes.
STL Finder - Great tool to find 3D models to print.
507 Mechanical Movements - Drawings and animations of mechanical movements. Fascinating.
Web based GCode viewer - Used this a few times!
My Mini Factory - Verified printable models. Scan the world is particularly good.