Instagram's main feature is that it is based on visual material. Unlike Facebook and Twitter, which support a wide range of information and media, everything on Instagram concentrates around images or videos. When you post a photo to Instagram, it appears in your followers' feeds, where they can like, comment, or share it. The more likes or comments your post receives, the more "relevant" it gets and the higher it appears in your followers' feeds. This algorithm is crucial to Instagram's success.