I recently used Jaccard similarity as a measurement of distance between two sets of online articles. It’s amazing how versatile it is for all sorts of weird tasks.
I uses to use Jaccard similarity combined with w-shingling at the character level to detect clusters of fraud sites. It was surprisingly effective, because it was able to pick up common patterns in the code even if they used completely different styles and text.
Interesting - I also used Jaccard similarity to classify clusters of malicious ad traffic schemes. The idea worked well. It was unclear if the similarity was due to mimicry or authorship, but that did not matter for our use.