This sounds good to me, and "mask" sounds like a good term for it. I'm in favour of it being converted to the best spoiler code we can when sending to LJ, and working in comments as well as entries.
In email notifications it would need to work like spoiler text rather than a cut, though - I'd want to be able to read it by highlighting within the email.
no subject
In email notifications it would need to work like spoiler text rather than a cut, though - I'd want to be able to read it by highlighting within the email.