Looks like it doesn't work anymore, but at one point someone styled reddit to look like you were reading a Word document: https://pcottle.github.io/MSWorddit/
The idea was that you can open your usual work editor (word processor, IDE, spreadsheet, ...) and use it as a chat client.
It was more like a proof of concept, it didn't work that great and wasn't really useful. Also such a tool is likely to trigger all kinds of alerts in antivirus software, for good reasons.