Cloud Giants are the most social of the giant breeds. While all types of giants form societies based on their role in the Ordning, for Cloud Giants, their society is the Ordning. Cloud Giants in the Forgotten Realms were once the nobles and generals of the ancient giant kingdom of Ostoria, and even in the present they're often the nobles of giantkind, being just behind the distant Storm Giants on the Ordning. Cloud Giants base their ordning on wealth, but not just having it. They're not dragons, content to hide things away in hoards. To a cloud giant, the display of wealth is just as important as its possession, so cloud giant dwellings are often filled with artifacts, magnificent works of art crafted from valuable material, and rare commodities from around the world.
Cloud Giants have a tendency to demand tribute from surrounding areas to further enrich their hoards. They see this as only fair- after all, the very presence of a Cloud Giant deters other potential threats, and they could just take what they want, but they're being polite about it, so how about some gratitude here? Beings who pay such tributes tend not to see it the same way, but they're also squishable so who cares. Cloud Giants worship Memnor, a deity of control, honor, the mind, and pride. While Memnor himself is Neutral Evil, cloud giants tend to aspire to one-half of his traits- Neutral Good cloud giants see him as a god of honor, knowledge, and society, while Neutral Evil cloud giants see him as a god of trickery and deception. A class of Cloud Giants known as Smiling Ones seek to emulate their deity in all forms of trickery, and wear masks that are half-smiling, half-frowning. Other cloud giants tend to be leery of them, since their commitment to deception often oversteps normal bounds of decorum.
And for those of you wondering why they're called Cloud Giants, yes, they do live in the clouds... or at least, the highest-ranking of them do. The secret to making the great cloud citadels was lost with Ostoria, so most of them make do with general high places, like mountain ranges. Wherever they choose to live, cloud giants have to deal with a constant stream of minor nuisances, like adventurers, coming to grab them some of the shiny things the giant has collected. Presumably, this includes tricky peasant boys climbing up magical beanstalks.
In 5th edition, Fog Giants are cloud giants who turned to banditry due to losing their wealth and being desperate to reclaim it to get their position in the Ordning back.