Sociology is a science which attempts the interpretive understanding of social action to arrive at a casual explanation of its course and effects. Sociology seeks to formulate type concepts and generalized uniformities of empirical processes. (History, on the other hand, is interested in the causal analysis of particular events, actions or personalities.) Action is human behavior to which the acting individual attaches subjective meaning. It can be overt or inward and subjective. Action is social when, by virtue of the subjective meaning attached to it by the acting individual(s), it takes account of the behavior of others and is thereby guided. Social action may be oriented to past, present, or predicted future behavior of others. Others may be concrete people or indefinite pluralities.
Not all action is social: if it ain't oriented to the behavior of others, it ain't social. Also, it is not merely action participated in by a bunch of people (crowd action) or action influenced by or imitative of others. Action can be causally determined by the behavior of others, while still not necessarily being meaningfully determined by the action of others. If I do what you do because it's fashionable, or traditional, or leads to social distinction, its meaningful. Obviously the lines are blurred (pp 113-114), but it's important to make a conceptional distinction.
Uniformity of social action = action which is wide-spread, frequently repeated by the same individual or simultaneously performed by many individuals and which corresponds to a subjective meaning attributable to the same actors. Usage: probability of a uniformity in the orientation of social action, when the probability is determined by its actual practice ('it is done to conform with the pattern). Custom: usage when the actual performance of the action rests on long familiarity. Non- conformance is sanctioned externally. Action can also be uniform if the actor acts in his self-interests. The uniformity rests insofar as behavior is determined by purely rational actions of actors to similar ulterior expectations.
There are 2 kinds of meaning: 1) actually existing meaning in a given concrete case of a particular actor, or average or approximate meaning attributed to a given number of actors; and 2) theoretically conceived pure types of subjective meaning attributed to hypothetical actor(s) in a given type of action (like an ideal type).
The line between meaningful action and reactive behavior w/o subjective meaning is ...