I have a frankly ridiculous number of online presences (full list here), but here are the best ways of keeping tabs on me:
You should bookmark my Writing Page. It conveniently lists all my latest writing from the different sections of this website (articles, reviews, newsletters, and sidelines). For my fellow geeks, there's even an RSS feed.
Please follow my Facebook page. I post links to most of my new writing there, along with the occasional photograph. I typically only post one or two updates a week.
I am @friendsofdarwin on Twitter. I tweet a mix of personal updates, history of science stuff (mainly of a Darwinian nature), and anything else that interests or amuses me.
You should definitely subscribe to my ‘Rich Text’ newsletter. It is short, perfectly formed, and not at all spammy. I tend to send out about one newsletter per month.
I post to my Instagram photos feed roughly once a day. I tend to publish a mix of serious photos and fun snaps.
My Flickr page contains thousands of photos going back many years. I tend to post to it in batches, usually after going out for walks.