To get started simply paste a YouTube URL into the Timelinely homepage to get started. Once you have entered the URL for a video, a new screen appears that allows you to add tags or annotations to the timeline of the video. You can do this while the video plays or you can simply jump to a place on the video to add annotations. Your annotations can include text or images. As you can see in the screenshot below, I included an image of my friend Tom Richey in the annotation that I made on one of his YouTube videos.

Before you get too involved with Timelinely it’s important to note that you’ll have to create an account in order to save and share your work. You can create an account by using your Google account, by using your Facebook account, or by signing up with any email address. You can share your annotated version of a video via email and social media. 

Applications for Education
One of things that I like about Timelinely is the option to include pictures in your annotations. I can see that feature being used to include an alternate example for students to view when watching a math lesson.

I’m not sure that Timelinely is any better than a handful of similar services, but it is nice to have options