The Black Sun is as large as a few football fields, and has specific rules about gravity and stuff, so you can't just pass through other people's avatars like on the Street. The avatars all look fairly realistic, and so do the daemons (which are pieces of software that generally look like people, but exist to run errands and such).
Hiro calls up a program called Bigboard to help him locate info by hacking The Black Sun's operating system. It tells him where his friend Da5id is, and he also sees a woman talking to Da5id, whom Hiro recognizes immediately due to her mannerisms.
This is Juanita Marquez, whom Hiro's known since they were students at Berkeley. Ah, Berzerkeley.
Hiro remembers her as being serious, geeky, and sharp-tongued. Later, they worked together at Black Sun Systems, Inc., where Juanita was in charge of avatar faces, which at the time were not very advanced.
Back then Hiro's upbringing had not really prepared him to meet someone like Juanita. He'd grown up an army brat, constantly moving around, and women were predictable and sweet-natured in his world.
Like many programmers, Hiro thought he was too smart to be sexist. But Hiro realized, belatedly, that Juanita was awesome and classy—perceiving her as dowdy was a problem on his end.
He went to her office back when they were coworkers, after this realization, and asked her about the portrait of her grandmother that hung over her desk.
Juanita explained that her grandmother was her role model, and launched into a story about how she'd had a pregnancy scare while a teenager, and simply by looking at Juanita's face, her grandma knew exactly what was happening.
According to Juanita, the sheer genius of this struck her a decade later, in grad school: The human mind can process an amazing amount of information if it's packaged correctly. Which is precisely what the human face does—it conveys information quickly and efficiently.
Hiro asked Juanita out shortly after she blew his mind with this, and they dated for a few years, but then broke up. Juanita went on to date and later marry Da5id, though they got divorced a couple years later.
Since then, Juanita's made it big based on her stock in The Black Sun. Hiro had to sell his for his dad's hospital bills, and then to put his mom in a retirement community in Korea.
So Hiro's dirt poor, which isn't awesome, but he looks at his parents' happiness as his own personal fortune. And even if his life is crap in the real world, he's a warrior prince in the Metaverse.