26 votesIT should work now! commented
This was discussed at length in another thread requesting similar for gmail's use of + in their addresses. I'd love it too as I use a different <email>+<sitename>@gmail.com for every website I register on.
Troy's feedback was he's crunched the numbers and can't justify the commitment of time given the low % of addresses using the convention mentioned.
It's a shame because I have to consider re-naming all my accounts with the vanilla address so that I can find (and be notified of) the address in a breach.
1,413 votesIT should work now! commented
Maybe as an alternative you could allow a 'batch' search feature, where I could load all my <name>+<website>@gmail.com addresses and a report with a matched results summary for each?
The onus would be on me to maintain my list of addresses (not hard, a CSV export from 1Password would do it).