Most of the time when I am reading and spot an error I let it pass. After all, if I was to contact the publication or website every time I spotted a mistake it would take up a considerable amount of time!
Occasionally, however, I find a mistake to be confusing for the reader, so worth intervening.
One recent example: I subscribe to MUBI to watch films at home. They send out a monthly newsletter called Notebook.
In the latest edition they had an interview with Isabelle Huppert about her work with the director Claude Chabrol. In one of the early paragraphs it said: “The part established Huppert’s comfort with discomfort and penchant for abrasive characters with often unreadable inferiorities.”
This struck me as wrong, both within the context of the article and my knowledge of the films being discussed. I was sure they meant to write “unreadable interiorities”, so I contacted the editorial team about it (and another mistake which I mentioned in passing).
Happily the editor was quick to respond thanking me for the spot, which was corrected immediately online. So everyone is happy: me for making the effort; the editorial team for expunging a couple of mistakes; and hopefully readers who would otherwise stumble over this sentence and come away with the wrong impression.