I've never heard of "social atomism" in any of the literature I've read before, so I'd say Objectivism doesn't have an opinion on it as such. However, the article you mention seems to define it as the idea that society is nothing more or less than a collection of individuals. Working with that as a rough definition, I can say that Objectivism certainly holds that society is made up of individuals, and that the rights of the individual are primary. Even further, Objectivism holds that there can be no such thing as the "rights of society" since such rights, ultimately, simply refer to the rights of each individual.
There are two observations I'd make of the article. First, the author doesn't seem to accept that a definition is not identical to the concept (see the Ayn Rand Lexicon for details). In particular, the concept of "society" he ascribes to the "social atomist" position ignores all aspects of the concept which aren't explicitly included in the definition (e.g., laws, customs, etc.). He then proceeds to attack the "social atomist" position on those grounds.
Second, later in the article he attacks the idea of libertarianism as a whole in his "Good for Each, Bad for All" section. Most of the objections he raises are same ones Objectivism has with libertarianism, and they boil down to: libertarians believe in freedom, not individual rights. Freedom means that no one is restraining you from behaving however you want: no matter how you want to behave. Individual rights means that a person is restricted from taking certain actions against others (and their property), but is otherwise free to do as he likes. This is a crucial distinction, and is one of the main differences between Objectivism and libertarianism.
answered Apr 19 '11 at 13:40
Andrew Miner ♦