As shown in this question, default user avatars (like mine) are identicons and are generated with the user's email (where provided) or the user's IP address (where the email is not provided).
Given any identicon and information of whether it was generated from an email or IP address, can the email or IP address be identified? If yes, post my email in a spoiler (I registered an email with my account). If no, provide reasoning why.
It used to be possible, as Gravatar identicons are a graphical representation of the MD5 hash of an encoding (trim leading and trailing whitespace and convert letters to lowercase) of your email or IP address. Both of these things are small enough to make brute force feasible. Nowadays, Gravatar includes a secret salt in the hash operation, making it impossible to even attempt to brute force them without knowledge of that secret. The secret is stored somewhere on the Gravatar servers. If someone was able to obtain that secret, they would be able to brute force the email or IP address.
Note that Stack Exchange's Area 51 site still does not use a salt, unlike the rest of the network.