If unsure, paste into https://huggingface.co/openai-detector and check. If the detector says 99% fake, it is very likely fake. The detector can mistake ChatGPT generated text as real (maybe because it was trained to detect GPT2), for example one text I generated scored 99.94% real. I suspect it is better to paste just a few sentences (especially for a generated blog partially modified by a human?). Although there are legitimate uses, such as people using ChatGPT to correct their grammar — https://news.ycombinator.com/item?id=33884842 . . . Also if I find GPT generated comments that are not clearly labelled, I flag and downvote.