As can be read here: https://www.reddit.com/r/privacy/comments/4cr8za/the_warrant_canary_is_missing_from_the_2015/ referring to https://np.reddit.com/r/announcements/comments/4cqyia/for_your_reading_pleasure_our_2015_transparency/
The warrant canary is something a company can display, stating they did not receive a National Security Letter in the last year. NSL's are gag orders, forcing companies to provide all info LE wants 'in the interest of national security'. As it is forbidden to communicate that a NSL has been received, a warrant canary uses this fine line that it is not forbidden to not post that you didn't receive one. Essentially this means that they did receive one, although they cannot talk about it.
In short: No subpoena's are needed anymore, since LE can ask info under the National Security Letter. This also means that Reddit does not has (or may?) inform you about the info they gave to LE about you.
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