[humbledrone]

I love this feature, but unfortunately I've found that probably 30-40% of the websites that I supply with my email address will not accept it due to the "+" character. It seems like travel-related businesses are some of the worst offenders -- the vast majority of airlines and hotels seem to balk at the "+", which is frustrating, because "+travel" is one of my favorite filters.

[kiwidrew]

Amusingly, this is almost certainly due to the legacy backend systems which still use a six-bit character set, and this set doesn't include helpful things such as lowercase characters or the + symbol.

[bambax]

Totally agree. For me it's a way to assess the quality of the website: be wary of websites that complain that emails can't contain a +.

If you have your own domain (which I think most people have on HN?) you can use different usernames to the same effect, or a different separator.

But even if it worked all the time it's only part of the solution.