Posts can now have several slides. Meaning, you can upload more content to a single post. If a post has more than one slide you'll see slide navigation buttons at the top-right corner of the post (next to views). Click the arrow pointing to the right to see the next slide of this post.
On mobile the slide navigation buttons are found under the other post buttons.
New post submission has been re-designed for slides. If you want to have just a single slide for the post (like before) only use the first slide boxes. Otherwise just click on the next slides tab and use the boxes below. Title, language and topics are the same for the whole post. Messages, links and images can be different for each slide. There is a maximum of 10 slides per post.
This feature should help you upload more content to a single post and it can also be used in very creative ways.