Let's start with:
Senses
Dataform characters have visual, auditory, and other sensory cortexes just like physical characters do (unless they've intentionally removed them). Therefore, dataform individuals can send each other sensory information: images, videos, scents, tastes, sounds, etc. They often communicate with one another in this way. However, dataform characters don't sense those things - properly speaking, they interpret them. If they have no dedicated remotes, they operate without Nanotech scores, unable to sense the physical world. What does that leave them with? What's that like? What actual senses do they have?
By a sense of internal lag, dataform characters can tell whether they're running on a single server or multiple servers. They can pull themselves together to consolidate on one server, or distribute themselves across multiple servers, assuming their hosting arrangement allows for that. This is like the sense of proprioception that physical humans have, which tells us where different parts of our body are. Consolidation is like sitting with your legs pulled up on he chair; distribution is like being sprawled out over the arms. Being distributed is definitely being exposed: if one server crashes or is destroyed, you've lost some memory because of that. On the other hand, it gives you a broader feel for other things.
Dataform characters can feel infosphere traffic - packets of data streaming past them. They can feel a direction to that flow if they're a little distributed. This is probably a little like feeling a breeze with your sense of touch. If the traffic gets really intense, then the flow might feel constricting, like being wrapped in a blanket.
System messages sent to Dataform characters might come in as textual information, or as packets of data that are consciously examined and evaluated. However, that takes up conscious attention and intent. Those things are heavy on processing power. A faster, easier, and more powerful way for those messages to be interpreted is through an individual's subconscious. Low-memory warnings can create feelings of pressure and anxiety. Acknowledgements from network transmissions might feel like the nice touch of companionship you get when someone waves back at you. A loss of infosphere connectivity would be a feeling of sudden loss and uncertainty, as one might feel when a restaurant suddenly goes quiet. Certainly some error messages would be better interpreted as text, but others can be more efficiently handled through gut feeling.
Being distributed has an effect on your "gut" senses as well. You're receiving messages from multiple different systems. They're likely to be muted, so as to compensate for the number that are coming in, so you'd have to concentrate to figure out what's happening in any one particular place. If you start feeling anxious and rushed, it means that every computer you're distributed through is having memory issues simultaneously. This might allow you might detect viruses that are exploiting multiple systems, or municipal/governmental draws on communal computing power.
You could intentionally link particular things to your gut senses. For instance, a Mechanican politician might need money for the next campaign, and could link his bank balance to his sense of well-being. Running a wormhole transmission (which costs money) would be sort of like the feeling where you've eaten too many cookies. You'll be fine eventually, but you know you shouldn't do it too often.
Further suggestions are welcome.