Photocasting allows Mac users to share photos with friends and family. The feature will automatically upload the photos to a server and publish an RSS feed.

Other users subscribe to those feeds through iPhoto or a feed reader, allowing them to automatically receive updates when new photos are posted.

The Photocast feature uses a new element to indicate the date on which a photo was taken, even though there are already numerous alternatives that perform the same function. IPhoto, however, will not recognise the standard date elements.

Introducing new elements not only prevents common feed readers from accessing Photocasts, it makes it harder for third-party applications to introduce similar features that interoperate with iPhoto.

The non-standard elements could prevent the Windows screensaver from displaying iPhoto Photocasts, for example.