I keep seeing people talk about the signal as an "alien virus" or a biological weapon, and it just doesn't line up with the evidence. Everything we see, from the perfect coordination to Carol's immunity, points to a simple truth: the signal is a piece of self-executing software, an RNA Computer Worm, that treats human beings as available hardware. 

Honestly, viewing the signal as a piece of self-executing software is the only thing that makes all the weird mechanics line up. Real viruses don't coordinate people, sync their behavior, or respond to signals, but worms do, and they are designed to spread through a network and keep all the infected nodes talking to a central Command-and-Control (C2) channel. 

This is why the hive mind looks so synchronized, it’s pure code enforcement. The biggest giveaway is that scene where Manousos scans the radio frequencies and finds that weird, repeating noise; that is the C2 channel, because while biological viruses do not phone home via radio waves, worms do when they need updates. This distinction also explains immunity: if it were a virus, Carol would have antibodies, but if it's software, her immunity is simply hardware incompatibility. 

This whole setup changes the stakes, too, because I'm convinced this worm is actually traveling the galaxy, jumping from civilization to civilization like a program looking for more devices to infect. It autonomously infected the planet 600 light-years away, and when they built the transmitter, they just became the next jump drive. The worm isn't interested in destroying us; it's just operating biological code, looking for new host hardware to run on. 

This is exactly like the Morris worm from the '80s. Once the Morris worm was (accidentally) set loose, it didn't need the coder behind it anymore; it contained all the code necessary to autonomously keep infecting 10% of the entire working internet. This alien RNA worm is the same idea, just scaled up: somebody created it, let it loose millennia ago, and now it's just bouncing around the galaxy looking for new hosts. The worm has two modes: it uses physical contact (kissing, aerosols) to build its initial network, making it look like a virus at first, but the radio signal is the C2 channel waiting to send coordinated instructions and updates to the entire infected population at once. 

The simplest explanation is: it’s a self-running alien worm written in RNA that uses living organisms as its hardware. 

What do you guys think? Does this fit the show better than the standard virus theory?

This is a video on the Morris Worm.

The Pluribus Signal is a Galactic RNA Computer WORM, not an alien virus.