- This site tracks where I go and what I do every day. Most of the data comes from various apps on my phone.
I've measured my heart rate 462 times and typically it beats 69 times per minute. In the past 119 days, I've pushed 1,399 commits to this site, gone on 29 runs & eaten 15 burritos. I love a good burrito.
This seems extremely tedious to do, but I find it interesting. Screw Facebook privacy concerns - he has every place he's gone to, every run, his pulse, vitamin levels, etc. all tracked. Why?
Google seems to want to make this easier to do.
His website is pretty sweet, though.
It's totally easy, though. 1) Runkeeper will totally track your workouts. 2) Myfitnesspal will totally track your calorie intake, nutrient level, you name it. 3) Fitbit will totally track your every step. The HDL, LDL and glucose need to be taken directly, but glucose levels are easy to do. HDL and LDL require blood testing so I expect those are a bit more static. Really, this is just a pretty face that amalgamates the feeds from a few different fitness tracker apps. If I had his front-end I'd have the exact same level of detail. I wouldn't have the run at Ko Samui, though. Jealous. 
I use it for calorie counting, which has helped me lose (and keep off) about 40 lbs. Honestly, Runkeeper just lets you enter exercise into MyFitnessPal, and MyFitnessPal lets you know you've earned a cookie. The rest of the data is readily available, but of no particular interest to me, anyway.
All of that is true but don't discount the effort required to pull all of these different sources together, get them into some DB and then layer the fancy site on top. I have no interest in his data but I'm really impressed that he was able to get it all up and running so sweetly.
Well, let me redefine "easy" - The data is easy to collect. Repurposing it into another form is something beyond my abilities or interests. I just know that I have that data readily available to me, I just need to pull it from four or five different websites. In my mind, "melding 4-5 different websites into one" is a much less physically challenging task than "collect a dozen different types of human telemetry."
Funny as I had the opposite impression. Collating all the information into one place is more difficult than the effort needed to record the 4-5 different data sets in separate apps. Case Study: Location/Running/Walking/Cycling - I have Garmin 405 watch and all running logs can be exported to TRX files and overlayed on a map to show each session, it records heartrate during the session and calories burned etc. - I have apps on my phone (some I probably am not aware of!) that can track a huge amount of information when the Garmin is not recording. Steps, location, point in time heartrate records, Time spent in apps which can be grouped into Reading, Watching, Listening etc. If I so wished it can also track sleeping activity. - Fitbit - tracks all of the above without location or heartrates but good as a general "how active I was today" collection point. - Heart monitors - single point in time recordings for Glucose. I havent tried HDL/LDL but I assume it is similar? A single scan per day would be enough to trend results over. So from all of those relatively non invasive (apart from the glucose tests I already log this stuff regularly) data collections I should be able to easily produce something similar to this site right? Nope. Each one of those devices/apps/whatever has its own data format, its own interval timings (seconds, hours, ticks, epoch, instance etc). To just gather that information into something I can use I would need to write a custom conversion tool to map its data into my own version (canonical). I assume this is what he has done or else some of the data is only skin deep and not interrelated at all (heartrate has no references to location for example and cannot be easily linked without some manual intervention). I'm guessing (from a somewhat educated position) that that was the hardest problem to fix, and if he has solved it for the apps listed then that is the piece that will be monetized first, after all everyone and their uncle has a fancy UX but data is god.
Fitbit API Runkeeper API Myfitnesspal API That's everything but bloodwork. It all seems to be in the realm of Python.