The number of threads about different interpretations of the message keeps growing. Ideas get mixed as connections appear between topics that were independent at first. Conversations get tangled. It is even a bit difficult to keep track of everything that is happening at once.
A new idea that has appeared today is the prevalence of the number 5 in the message. The representation of the message "body" as the "starmap" has 5 clusters of dots, and the footer contains the sequence of bits 111110000011111.
Some participants are linking the number 5 to the short story A Sign in Space by Italo Calvino, from which the name of this project is taken.
In that story, 5 signs appear at some point. There have been even some attempts to give descriptive names to the 5 cluster in the "starmap": a star, a hummingbird, a mouse, something shapeless, and a very spiky star.
Another new idea is that the message could be the coordinates to a vast intergalactic library of universal knowledge.