Here's the characters that cannot be used in Blogger labels.
Labels are a way to easily categorize your posts. When you're writing a post, click Labels on the side and enter the labels you like, separating them with commas. Labels you've used before will show up below, and you can just click them to add them to the post.
When you publish your post, the labels will be listed with it. Clicking any of the labels will take you to a page containing only posts with that label.
