Here's a breakdown for the differing sites i use and why:
Facebook - Personal page (increasingly about family & friends)
Facebook - Boal Photography page (about Boal Photography)
Instagram - This started off to be a general sort of thing, but is increasingly becoming a portfolio for my portraiture and pro-photo-work.
Flickr - Again I have general stuff here, but mostly you'll find I only use it these days to upload images from the Christian Mission i'm involved with.
Twitter - I used to use this a good bit, but have found i've neglected it and don't really enjoy it that much anymore. It, when used is general.
And of course there's www.boalphotography.com