AI better known as Artificial Intelligence are beings that have been created to serve a specific purpose. They usually assist humankind in some capacity.
Throughout the Series
From conversations Poe has with various other AIs, many "sentient" AIs on Earth own various businesses, ranging from hotels to brothels to gambling. According to dialogue, many AI owned business is in decline as people do not like the business behavior of the AIs, which has been likened to "stalkers" and "clingy ex-girlfriends".
On Harlan's World, most AI's seem to be involved with archaeologists, and aid humans as assistants.
Most sentient AIs view humans with disgust. They see them as weak and in need of being conquered. Poe and Annabel Lee are the exception to this, as they view humans as interesting.