Layer 1 — the tools
What it was
Three ways to catch the same thing: work that wasn't the student's own.
Crot Desktop
CrotWinApp.exe — pick a stack of files, run a short wizard, get a comparison report. Free for the first three papers, shareware after that.
Crot for Moodle
A plugin (plagiarism_crot) that fingerprinted every assignment on a school's own server and flagged matches between classmates — nothing ever left the institution.
CrotPro
A connector service that checked submissions against English Wikipedia — by some estimates the single largest source of copy-paste it ever caught.
Layer 2 — why "crot"
The name
Крот is Russian for mole — a creature built for one job: dig, and don't stop until you hit something.
That was the whole pitch. Crot didn't skim a document looking for keywords, it tunneled through it line by line, hunting for the one buried paragraph that didn't belong to the student who submitted it.
Layer 3 — reach
Where it reached
K.I.D. Partners, Tokyo, carried Crot Desktop as its exclusive distributor in Japan. Teachers wrote in from further out still:
"Crot has an important role to fulfill in my teaching practice."
Mark Brand — NMMU, South Africa"Great component, very instant report. We appreciate the ease of use."
Jena, Germany"Crot has become a must-have add-on for our Moodle."
Torrance, California, USA"This is just what we needed. Thanks for the hard work."
Bulawayo Theological College, ZimbabweLayer 4 — why it stopped
Why it stopped
No scandal, no shutdown notice. The ground underneath it just changed.
Internet-wide checking depended on Microsoft's free Bing Search API. When Microsoft closed off free access to it in 2012, cross-institution and internet-wide comparisons went dark — Crot could still catch copy-paste inside a single Moodle course, but the wider dig was over. The shovel got put down quietly, the way most tools actually retire.
Bedrock — what's left
Still diggable
The Moodle plugin was open source from the start, and it still is. If you want to read it, fork it, or run it on your own server, it's all sitting where it always was.