In fact there'd be "tens of thousands" websites made with Python alone (Django et al), so the number of apps in total will be much higher.
Heck, people doing scientific Python are more than 10.000, and they write more than one new apps for their research every year.
I just dislike how melling basically pulled a number out of his ass, and then used it as "evidence" to back up his claims. I wouldn't even consider it a low-quality estimate, since he doesn't even try to justify or explain how that number was obtained.
In this case, "tens of thousands" could very well really be "hundreds of thousands". It could be significantly less, too. Regardless, it's purely speculative. Using such made up numbers makes his argument weaker than perhaps not using any such value at all.
