Bitcoin swap service advertisements, some tiny exchange advertisements, maybe gambling platforms.
I'm really feeling the 'cyberpunk 90's grungy Hong Kong' vibe- small billboards everywhere, just like every other user had ads on their signatures. some 'Mos Eisley cantina' energy where there is something of a rough underbelly, but also space for philosophers and aristocrats - a space for strange beings and robots from across the galaxy to gather.