To me IMHO always looks decidely ironic, even sarcastic, and decidedly unhumble. Anyone who says things like "Well, of course, I'm not an expert but.." is, in my experience, normally pretty confident that they are right.

But that's probably just a reflection of where I live. Irony isn't second nature in England, it's first nature. My impression is that Americans are more straightforward in the way they talk, but maybe that's just an oversimplified stereotype.

I never use these acronynms anytway - as 'Spaw said, if you say something, that means it's your opinion, unless you're lying, or unless you phrase it in a way that tells people to take it some other way. (Putting it in quotes, or maybe sticking ... are two ways of suggesting it might need to be taken with a little salt.)

But people have been communicating in writing for hundreds, indeed thousands of years. I can't see why suddenly it's considered that language itself isn't capable of conveying our meaning, and it has to be supplemented by codes and pictograms. Nothing against them, they're quite fun, but while they may add to the variety, they don't really make things clearer.

My basic rule is that anything anyone says is to be interpreted as being meant in a friendly way, if at all possible. If it isn't, that soon enough becomes clear. Why meet trouble half way? And I hope people take what I say the same way. If I'm being unfriendly, I generally make it fairly clear. (And argumentative isn't of course the same as hostile.)