Not a very good or well researched article. They left out many popular bootstrapped companies such as Imgur, one of the most popular image sharing services on the net or the fact that Github has VC money now.
"become the defacto image platform for reddit" makes you an outlier in the bootstrapping world I think. I think it's just much more useful to look at examples where the model is reusable - make B2B software for a specific market, and charge money for it.
But I do agree with your Imgur suggestion, that would've been an excellent addition.