On a FB group I'm on so nobody I know personally. A young guy (I think). He wasn't being nasty at all, it was along the lines of "Don't call me a Karen but..." I replied to him saying it was an offensive term and did he mind not using it. We had a brief, very amicable interchange where I explained it was rapidly becoming common usage but that it was actually quite sexist and ageist. He said he was really sorry, he'd never understood it in that way, and he edited his original comment! What a sweetheart.
I felt a bit daft challenging him but I do worry that this meme is starting to be an everyday way of putting down older women and I think it should be nipped in the bud.
Now I worry I should have just let it go and that by complaining I have left myself open to some prat calling me... a Karen...