Elliott C. Back: In Aere Aedificare

So far, the answer is clearly no. Go vote yourself on Expelled: The Movement’s website.

I saw this physics interview question pop up on the internet, and thought it might be worth discussing:

A plane is standing on a runway that can move (some sort of band conveyer). The plane moves in one direction, while the conveyer moves in the opposite direction. This conveyer has a control system that tracks the plane speed and tunes the speed of the conveyer to be exactly the same (but in the opposite direction). Can the plane take off?

There are a number of forces here that apply: gravity, the force of the engines / airspeed / lift, and the drag of the wheels against the conveyor / the speed of conveyor. However, the wheels provide essentially a frictionless boundary between plane and ground; unlike car wheels, the wheels of an airplane spin freely in place. So, as the conveyor belt speeds up, the airplane stays in place, but its wheels spin at the same velocity. Furthermore, the lift of the airplane is relative to its airspeed, and its engines push against air. So, the airplane will accelerate forward and take off as normal.

The commenter “Max” has a nice summary as well: “A comparable example in my mind would be a car on a treadmill. If the car is being pulled along by a winch and the wheels are turning freely then the car is going to be pulled at an identical rate whether or not the treadmill is there or not (assuming as you did that the treadmill’s speed is inverse to that of the car).”

When John Graham-Cumming asked the question How Many Users Does Digg Have?, there were a few things he couldn’t tell you, since his data consisted of randomly self-sampled users. Well, with the power of two PHP scripts, we can pull large amounts of user data and form queries. Our first question is how has DIGG grown over time?

A graph of 187,054 digg users, randomly plotted against when they joined

This doesn’t tell us much, though, about how many DIGG users there actually are, or how active they are, so I plotted a histogram of the number of times these 200k users’ profiles had been viewed; the answer, unsurprisingly, is not very often in most cases:

83% of users had less than 50 profile views

And what about users who are active? How many people are digging stories every day? The answer is very few. I took a sample of 29,225 users from the previous sample (randomly) and used the DIGG API to query for their last digg. It turns out 31% (9125) had never dugg anything! After I removed those, here is the histogram I got:

About 15% of Digg users dugg a story in the last week

Concluding thoughts

Digg boasts an official tally of 2.2M users, but at most 20% of them can be considered real, active users. That would bring their user count down to 440,000, far far less than a popular web 2.0 boom child can boast about, and significantly hurting that $300M (or ~$700 a user) valuation that they keep trying to get.

Code Appendix

The {digg user, time joined, digg id, profile page views} information was gathered by the following script:

<?php
    error_reporting(E_ALL);
    ini_set(‘user_agent’, ‘My-Application/2.5′);
    ini_set(“include_path”, “.:/usr/share/pear”);
    require_once ‘Services/Digg.php’;
    require_once ‘Services/Digg/Response/php.php’;

    $base = ‘http://services.digg.com/users/?appkey=http://example.com&type=php’;
    $data = unserialize(file_get_contents($base.‘&count=0′));
    
    $total = $data->total;
    echo “There are $total total users\n”;
    echo “ID,Number,Name,Date,Views\n”;

    for($i = 0; $i < 1000; $i++){
        $offset = rand(0, $total - 100);
        $data = unserialize(@file_get_contents($base.‘&count=100&offset=’.$offset));

        $j = 0;
        foreach($data->users as $user){
            $page = @file_get_contents(‘http://digg.com/users/’.$user->name.‘/’);

            if(!$page)
                continue;

            preg_match(‘/id=”userid” value=”(\d+)”/i’, $page, $matches);
            echo $matches[1] . “,”;
            echo ($offset + $j++) . “,”; 
            echo $user->name . “,”;
            echo $user->registered . “,”;
            echo $user->profileviews .“\n”;
        }
    }
?>

As many of you know, Om Malik recently had a heart attack. According to a post made on January 3, 2008, he’s giving up the lifestyle that may have caused his cardiac arrest:

Now living a healthier life isn’t just one of my New Year’s resolutions, it’s doctor’s orders. Friends and family have purged my apartment of smokes, scotch and all my favorite fatty foods — I am even going to be drinking decaf. I won’t be refashioning my avatar’s stogie with a celery stick, but I will be taking better care of my health.

The New York Times published a piece about Om Malik’s heart attack which blamed blogging, which they quoted Paul Kedrosky as “a recipe for stress through the roof.” However, I’d like to make it quite clear that blogging is not bad for your health. Rather, another common problem in the United States–which some have called an epidemic–is probably to blame:

Om Malik, by Jon Arnold, under the bastion of fair use

Obesity. According to Obesity In America, “approximately 127 million adults in the U.S. are overweight, 60 million are obese and 9 million are extremely obese.” Blogging can be stressful, but it’s just a red-herring. Being overweight is a more likely risk factor for your heart’s health.

Best wishes to Om with his recovery. Best of luck in the new year with your new, healthier lifestyle!

Note that I’m not a Medical Doctor, and this does not constitute medical advice, nor does it establish any kind of doctor / patient relationship with you readers.

According to a GigaOm article Google Trends Predicts Hillary as Dem Nominee, “current Google trend lines show Clinton beating Obama and Edwards.” Unfortunately they neglect to compare any possible Republican nominees, or any other candidates for nomination, such as our infamous Ron Paul, who easily pwns Hillary’s search volume by orders of magnitude:

Can Ron Paul steal the Republican nomination? According to his Google trends graph, he can! Maybe democracy is coming…