Is there a scheduled ecnrypted message relase service online?

Is there a scheduled ecnrypted message relase service online?

Is there a service where I can encrypt a message, and is not released
until a certain date?
For example, if I want to write a message that cannot be read until next
January 1st i'd do:
Go to this site and retrieve the public key corresponding to next January
1st.
Encrypt the message with that key and release the encrypted message.
When January 1st arrives, this site would release that private key so
everyone can decrypt it.
Public keys must available early, while private keys are released only on
target date.
The site could optionally host the messages too.
Would a service like this make sense?