Microsoft has renamed its free online storage service as Windows Live Skydrive. The company has also relaunched the service as a beta preview open to anyone.

Formerly called Windows Live Folders - the name under which it briefly made a public appearance in mid-May before vanishing again into invite-only testing - the service requires users to log in with a Windows Live ID. Most people are familiar with Live ID from accessing Hotmail, now called Windows Live Mail, or using Windows Live Messenger for IM.

Skydrive's storage allowance is 500MB; it lets users create and designate folders as private, public or public-but-invite-required; and can be accessed using either Internet Explorer (IE) or Firefox. New features or enhancements that debuted in the refresh include image thumbnails and file uploading using drag-and-drop. The latter, however, relies on an ActiveX control, and so can be done only when using IE when accessing Skydrive.

Not a backup service - it lacks the tools to automate file transfer from local PC to offsite server that, say, Mozy Online Backup provides - Skydrive limits individual uploaded files to 50MB or less. Currently, the best is restricted to users in the US, the UK and India.