Back in the day, sharing a compilation of music with your friends was a fairly complex process, since you needed to copy songs to a cassette or CD in the right order and then physically hand it over. These days, you can simply post your playlist on your Tumblr blog, either by piggybacking on an external service or by taking advantage of Tumblr's tagging feature.

Spotify

Because Spotify integrates with Tumblr, posting a playlist you've put together in Spotify only takes a few clicks. When creating a playlist, you should ideally include only music from the Spotify library, avoiding MP3 files stored on your hard drive, since although the playlist will show information for the hard drive files, they'll be grayed out and unplayable. Right-click the playlist in Spotify and select either "Copy HTTP Link," if you're using the standalone Spotify software, or "Copy Spotify URL," if you're using the Web player. Switch to the Tumblr dashboard, create a new audio post, click "External URL" and paste the URL into the text field. The URL can start in two different ways -- "http://open.spotify.com/" and "https://play.spotify.com/" . In the latter case, you'll need to edit the URL to match the former for it to work in Tumblr.

SoundCloud

SoundCloud also integrates with Tumblr in exactly the same way as Spotify, so posting a SoundCloud playlist to your Tumblr blog follows a similar process. Click the "Share" button on the playlist, copy the URL that appears and switch to the Tumblr dashboard. Click "External URL" and paste the link into the text field.

8tracks

The 8tracks website is expressly designed for the creation and sharing of playlists. Once you've created your playlist and given it a title, description, cover art and tags, click the "Share" button on its page and select "Embed Player." Copy the embed code that appears, switch to the Tumblr dashboard, create a new video post and then paste the embed code into the "Embed Code or Video URL" field.

Tumblr Posts

If you don't want to rely on an external service, you can post your playlist to Tumblr in the form of individual audio posts, one per song. Unlike when you use an external service, you won't be able to get the playlist to play all the songs in a row, but you can still get them all to appear on the same page by tagging them appropriately and then linking to the page for that tag on your blog. When creating the audio posts, give each a unique tag that you have never before used on your blog and will never use again. The tag should be specific only to posts belonging to that particular playlist. Add a link to the following URL in the caption for each post, replacing "blogname" with your blog name and "yourtag" with your chosen tag, with pluses instead of spaces:

http://blogname.tumblr.com/tagged/yourtag

The URL points to the tag page, giving your readers a way to reach the full playlist from an individual post.