Simon Willison’s Weblog

13 items tagged “kellanelliottmccrea”


Dropbox: Sharing our Engineering Career Framework with the world (via) Dropbox have published their engineering career framework, with detailed descriptions of the different levels of the engineering (as opposed to management) career track and what is expected for each one. I’m fascinated by how different companies handle the challenge of keeping career progression working for engineers without pushing them into people management, and this as a particularly detailed and well thought-out implementation of that. # 13th July 2021, 11:31 pm


Friday wins and a case study in ritual design. “Culture is what you celebrate. Rituals are the tools you use to shape culture.” # 8th June 2019, 6:14 pm

Questions for a new technology. Kellan poses 8 questions which should be asked of any technology that is being proposed for inclusion in an existing tech stack. I’m particularly fond of “Will this solution kill and eat the solution that it replaces?”. My rule of thumb these days is that new technology either needs to make something possible that isn’t possible at all with the existing stack, or it needs to represent at least a 3X productivity improvement in order to compensate for the switching and retraining costs across a large team. # 6th February 2019, 4:10 am


I’m still a novice to the healthcare space, but if I walked away with a single insight, it’s that the problems of the US healthcare system are very tractable. The high cost and mixed results are unique to our system. There are incumbents fighting fiercely to maintain the status quo, but no more so than in other industries that technology has overturned. The regulatory environment is complex, but again not uniquely so. There are industries where one has to dig to find the problems that technology is well suited to solve, but US healthcare, an industry that communicates via fax, is not one of them.

Kellan Elliott-McCrea # 10th March 2018, 1:11 am


With Flickr you can get out, via the API, every single piece of information you put into the system. [...] Asking people to accept anything else is sharecropping. It’s a bad deal. Flickr helped pioneer “Web 2.0″, and personal data ownership is a key piece of that vision. Just because the wider public hasn’t caught on yet to all the nuances around data access, data privacy, data ownership, and data fidelity, doesn’t mean you shouldn’t be embarrassed to be failing to deliver a quality product.

Kellan Elliott-McCrea # 18th May 2010, 6:21 pm

If you’re ever debugging a problem and you see the number 42-mumble-mumble-mumble-7295 you’ve run out of 32-bit storage. If you see 2-mumble-mumble-mumble-647 (2147483647) you’ve run out of signed 32-bit storage. 167-mumble-mumble-15 (16777215) you’ve run out of 24-bits and 65-mumble-mumble-35 (65535) you’ve run out of 16-bits of integers.

Kellan Elliott-McCrea # 25th January 2010, 8:11 am


We’re using the same trick on to avoid having to maintain a look up database, though we’re using base 58.

Kellan Elliott-McCrea # 12th April 2009, 4 pm

rev=canonical bookmarklet and designing shorter URLs

I’ve watched the proliferation of URL shortening services over the past year with a certain amount of dismay. I care about the health of the web and try to ensure that URLs I am responsible will last for as long as possible, and I think it’s very unlikely that all of these new services will still be around in twenty years time. Last month I suggested that the Internet Archive start mirroring redirect databases, and last week I was pleased to hear that Archiveteam, a different organisation, had already started crawling.

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Streams, affordances, Facebook, and rounding errors. I asked Kellan about scaling activity streams the other day. Here he suggests the best technique is not to promise a perfect stream (like Twitter does)—Facebook used to get away with 80% loss of update messages, but their new redesign has changed the contract with their users. # 19th March 2009, 2:02 pm


The only down side is everyone I’ve talked to at Freebase seems pretty solid on this being their proprietary secret sauce, because a good, fast scalable open source tuple store might actually jump start a real semantic (small-S) web after all these years.

Kellan Elliott-McCrea # 29th September 2008, 3:29 pm

Twitter, or Architecture Will Not Save You. Kellan is not an armchair architect. He also doesn’t mention Rails once. Well worth reading. # 29th May 2008, 1:16 am


Crowdvine, iCalico, Pathable, a Study in Collusion. Stitching sites together around a single user database using subdomains and simple signed cookies. # 12th July 2007, 11:09 pm


PHP Library Tips

Kellan Elliott-McCrea (author of the popular Magpie RSS parser): A Few Tips for Writing Useful Libraries in PHP. Kellan makes the interesting observation that PHP encourages a culture in which most development occurs in the context of either full applications or C extensions, with few people devoting themselves to releasing libraries.

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