Ummm... I do this a lot, actually. It conveys a bit of doubt and gives the comment an informal style.

So, I'm just overly sensitive? :-)
I promise I won't be offended when I see you use it, Wesner!

I use it occasionaly, and in fact just used it a minute ago in a blog comment. I do it intentionally, though, when questioning something that was written, to indicate doubt that they actually meant what they said. I do the same thing in my speech. Don't know where I got it from, though.

Uhm, I use uhm a lot to indicate it's somethign I'm thinking about/ not 100% sure etc. But because I usually spell it "uhm" rather than "um" or "ummmm..." I guess that doesn't apply ;)

Not sure on the Err.... one though. Isn't that human, and to forgive divine :)

Absolutely true Julia! I'm glad you pointed this out; it drives me nuts as well. Folks, when you answer a forum question, ask yourself if a tone can be inferred from the language you choose to utilize. Prefixing an answer with "Uhh...", "Erm..." or "Umm..." does indicate a slightly "holier than thou" tone and is neither helpful nor is it constructive. Not only would it be advisable to apply a little dash of "treat others as you would have them treat you", it's also quite frankly more professional to refrain from these judgemental little statements.

And some of us that have English only as a second language can be totally ignorant about the tone of the language. I use “uhm” as Wesner Moise and I never thought for a moment that it could be a problem. “Arrogance” – I will keep that in mind.

I think if it's someone I know, I can generally figure it out how an "err..." is meant to sound, but when it's someone I don't know, I'm more likely to read it negatively. (Or if I'm in a cranky mood to begin with. :-)) Good point about the ESL, though...