Register Your Spotify Account on ShareMyPlaylists
To add a playlist to ShareMyPlaylists (SMP) and use the social features, you need to connect your Spotify account to the site via Facebook or Twitter. Whenever you visit ShareMyPlaylists.com, a pop-up window appears, prompting you to sign in by using either of these accounts. The first time you sign in, you need to authorize SMP to have access to your basic Facebook or Twitter data.
In the case of Twitter, for example, you get redirected to a Twitter page, asking if you Authorize Share My Playlists to Use Your Account. Click Sign In to log in by using your Twitter username and password to confirm. You then get logged in to SMP via Twitter and are directed back to the site.
If you don’t have a Facebook or Twitter account, or would rather sign up separately to SMP, that’s possible, too. Just click the Register button at the top of the page to set up a separate username and password.
But it’s easier to use Facebook or Twitter, if possible, so that you don’t have to remember multiple passwords; there are handy links to publish your SMP playlists to either of these services.