Tags are an invaluable resource on Tumblr. They help users find your posts. They also assist you in organizing your content.
Depending on the Tumblr theme you select, the tags you choose for a post may or may not display on your blog. For those themes that show tags, the tags may appear along the bottom, top, or side of your post. See "Filed under" in picture below for one example:
It's important to choose tags wisely so that your content reaches as many users as possible. A few tips for making tag selections: