Linden Lab have blogged that the SL Share feature that was initially introduced to allow people to share photos, status and check ins on Facebook has now been extended to include functionality for Flickr and Twitter.
Personally I feel Flickr and Twitter are a much better fit for Second Life as both allow people to have their Second Life user name as their profile name, whereas Facebook is still in the bah humbug arena regarding pseudonyms.
In both cases they are taking advantage of features and requirements of the respective platforms, with Twitter the hashtag of #SecondLife is automatically added and with Flickr, they respect the fact that maturity ratings are sometimes required.
However there are also other funky features, such as post processing of pictures, as explained in the blog post :
This update will also introduce a set of post-processing filters that you can run your pictures through to create cool one-of-a-kind images! The new filters were inspired by the images posted to Flickr by Second Life Residents. With more than a million uploads, most of them enhanced by some post-processing, we thought it would be great to include this feature right in SLShare. These filters will work regardless of which social network you choose to share your Second Life pictures to.
However if you don’t like those filters, you can use the advanced features and create your own filters, the wiki has more details.
Now to take advantage of these features, you will need to download a special project viewer, which you can find here.