The downvoters were annoyed by bad punctuation. ;-P

Don't put spaces before commas or question marks.

Single question mark is enough. "??" looks sloppy.

> Don't put spaces before commas or question marks.

Actually, I do this all the time, when what precedes the punctuation mark is a URL. It just doesn't seem right to have the URL seamlessly run into a punctuation mark that isn't actually part of it.

URL a permissible exception to a rule that otherwise stands.

You can identify texts written by French people by the extra spaces (if they're careful or have a good word processor, it'll even be a non-breaking space).

PS: Spaces before smileys also permissible :-)

Yeah, I sometimes do it too, even though it doesn't look pretty.

Another possibility is to put <> around the URL; but that didn't work correctly on HN last time I tried.

Agreed , but I was unable to understand how it worked while taking off and landing .

People downvote over some dumb stuff sometimes on HN, but I'd be careful about posting a complaint about being downvoted that contains no other contents. It's against site rules and could get you in trouble.