It'd be great if the spambots end up talking to other spambots.
In the brief time between humanity's destruction and the Internet going down, Twitter and other social media will be just spambots re-tweeting each other. If we get that far, "AI" will be able to keep the Internet and the infrastructure it needs (power generation, power grid, actual cables) alive, and when aliens discover our planet, it will just find bots recycling the trending topics ad-infinitum.
In some Greg Egan book (Permutation City?) there are AI spam bots (that call you with full video and try to impersonate someone you know, then advertise a product) and AI anti-spam bots that take your calls and hold a conversation while trying to figure out if the caller is real.
The anti-spam bots are at a disadvantage because at some point in the arms race you have to make the bots actually fully intelligent, and then exposing them to spam 24/7 is torture and illegal. Spammers don't care about legal issues.
In the brief time between humanity's destruction and the Internet going down, Twitter and other social media will be just spambots re-tweeting each other. If we get that far, "AI" will be able to keep the Internet and the infrastructure it needs (power generation, power grid, actual cables) alive, and when aliens discover our planet, it will just find bots recycling the trending topics ad-infinitum.