I agree with ultramarina about the bragging. It always seems a bit off to me, no matter what's the topic.
When reading most of the posts, though, it seems to have turned into a discussion of people not being able to say anything (at least that is what I am feeling). I don't feel the need to tell people about my son's accomplishments. But I'd love to be able not to have to lie when others ask about school. So when one of my German friends says "Oh, he'll be going to first grade next year" I would love to just say "We're trying to figure out what to do for school as he doesn't quite fit in" (which is what I do say usually) but then if they get irritated as most German's get at the thought of somebody not going the traditional BM route (homeschooling is illegal in Germany) I would love for it to be ok to just say matter-of-factly that he is finishing 3rd grade in most subjects now at age 4 and that it really wouldn't be a good fit to send him to learn his letters and counting when he is 6. Without being accused of hothousing and forcing academics on a pure, innocent child who would never ever be interested in such things out of their won volition (just spend a day with him and you'll know all about his love for learning and how he drives us - not the other way around). For me that is all it is.
I would of course never lie in front of my son as I don't want him to feel like he should be ashamed or there is anything wrong with how he learns. I'd like him to just feel normal. So I guess as soon as he's 6 I might have to rethink my approach to the Germans - here is Canada at least most people accept homeschooling and you don't have to explain the why.
Cheers,
Stef