People gather with their friends, some in costume, some not.   As in social networking the core value is that people  just wanting to express themselves, share a bit about who they are, have friends and get some special attention.  Even in costume, most people are just who they really are -- though you get some who for the moment release who they  might want to be -- or play at something else. A few people behave badly, but the vast majority are good.

50,000 people walk in New York City's Halloween  parade.  Untold more, watch.  Rain or shine, or in last night's case, drizzle or drizzle.  Like a social network,  the larger the population the more apparent energy, the more people to see.  But when  the crowd gets too big, it's harder to focus, harder to tell a story.  The experience is less engaging, though still has some promotional value.   A person (or a brand for that matter) might be able to get a little impulse attention, but no depth of story.  In the  more focused venues -- a smaller party, a group at a cafe table, a deeper story can be told and we get to know each other better.  New York City's Halloween demands both for the best experience, the mass around the parade that sends a headline message for all to connect with, and the smaller groupings where we can really talk and get to know each other.

And so is the social flow of social networking.  The core value to most people are self expression and  sharing who they are, friends and some attention.   The massively large social network venues, bring the most reach and promotional or short awareness value, but get so noisy its hard to tell a deep story.  The smaller venues (such as a branded community site) can go deeper, but only for a smaller # of people.  The full spectrum well integrated, brings the most value.