The boom in digital cameras, and the increasing quality of mobile phone cameras, has created a glut of photos that sit on hard drives across the world. It’s now easy to take 20 photos where years ago you’d have taken one carefully-posed snap, counting down from 24 and wishing you’d have paid the extra for the 36 exposure film for your holiday. All these photos have got to go somewhere, but online sharing is so much more that the digital equivalent of a battered shoebox in the loft.

Flickr, as we’ve been using on The Big Picture, is four years old and hosts over two billion photos. Facebook holds even more, over four billion they say, but most are visible only to friends. So, given that they’re mostly the kinds of photos that we’d have faked a prior engagement to avoid, is the whole thing so popular?

It’s all about being able to find what you’re interested in, Flickr has a wonderful search facility based mostly on tags. Tags are labels that you (and others if you allow) add to your photos, often the simpler the better “tree”, “cat”, “beard”, “bullring”, and this opens all sorts of possibilities that just giving the title “Me at the seaside” couldn’t. Flickr also opened its database (through a thing called an API) to anyone, meaning that they could build websites that used and showed the photos or even photo-frames that gave you an automated and fresh slideshow.

You can watch photos added in realtime around the globe (there’s that geotagging again), you can get photos to spell out words,  or you can just bask in the nearly two million photos tagged “cat”.

You might not think that your photos are interesting to others, but the internet is a large place and there are always other people with similar passions. Groups are not only to show off your photos, but people do meet and form real communities (including in Birmingham). Flickr has developed its own algorithm to decide which photos are interesting (as closely guarded a secret as the recipe for Dr Pepper), you can see wonderful, inspiring, photography from around the world every day.

It’s the sense of community, as well as the easy co-existence between the snappers and the artists, that has made Flickr such a success - and keeping it focussed on one thing has prevented the annoyance that people eventually feel with most social web sites. Most commenters are also photo-sharers, and will offer advice and encouragement.

There are other sites that do similar jobs now, most are free to try. Whichever you choose, you’ll find that your enjoyment and interest in photography is only increased by letting them out there.

Someone out there is desperate to see that photo of your dog in a wig.