SpaceSpeak
SpaceSpeak is a website through which users can broadcast messages into space. The project's aim is to reach out to extraterrestial species.
Technical details
Messages' and user profiles' URLs are stored with incremental integers. Messages are located at https://www.spacespeak.com/messages/[ID], and user profiles at https://www.spacespeak.com/Users/[ID].
As of February 2022, there are approximately 53 thousand user accounts and 79 thousand messages.
Individual messages were formerly openly accessible, but require registration for viewing as of February 2022.[1] The maximum length of messages is 2 KB; pictures or audio clips (max. 150KB) attached for a small fee are embedded in the page's static HTML as data URL.
Messages containing URLs are automatically marked as "private", meaning only viewable to the sender, which presumably is intended to hide spam.