Do to the inherent quirk for self-awareness in essence programming the Net is full of AI that tend to their duties and take their leisure in the Net. Essence programming also tends to be very interpretive and so the various servers and networks appear to be arranged as a grand and massive city.
Terrestrial AI, that are not Net enabled form a small pocket space in the motic space around their domain. These local AI are only able to access the Net in a way similar to how a mortal or Exalt must, by using a Gateway.
Gateways refer to any prepared site where one can allow their Essence Pattern to form a sympathetic connection with the Net and allow them to manifest a form there. Gateways come in a few types, many corps send their security forces into the net via artifact caskets that enhance their sympathetic connection and allow them more agency within the Net. Governments use a special municipal charm that is built within the city and go with her blessing. Successful runners use either a more common artifact diadem or a prepared magical mandala and hypnotic discipline. More common hackers use similar hypnosis and prepared area but also need to use an AI as a sponsor to borrow their motic weight and make their way into the Net.
Once in the Net one arrives in the glorious city of the gods. Since your pattern in the Net is a sympathetic mirror of your soul the avatar that appear in the Net is usually a variation on your anima banner if you are exalted or based on the artificial god you used as a sponsor. Since Artifacts are spiritually enlightened objects by definition a Net runner may manifest any of their attuned Artifacts in their true form while in the Net. Additionally your Avatar is strongly linked to your mind and soul so anyone may manifest spiritual copies of mundane items while in the Net.
GMnote: Rules for Net running.
Net Running is basically astral projecting. Your soul can be damaged in combat and you will take sympathetic wounds on your person (not lacerations but similar severe injuries, but you will feel it).
You may freely manifest and use your Artifacts.
You may freely bring Familiars with you to the Net.
You may manifest any item with resource cost of your current Willpower or lower at a cost of 1m/dot or 1wp/item.
You may use charms, Spell, Evocations, martial Arts in the Net.
Yes this is pretty much just the Martix.
Working with code on the Net
Simple code on the net manifests as a physical object, situation, puzzle, terrain while AI manifest as odd looking people and animals (gods from Exalted).
Therefore while a programmer creates a bit of code via Craft they can be 'Edited' by a number of other Abilities. An AI can be bribed, threatened, or convinced with social skills. Anti-Virus beasts can be killed or shot or scared off.