The first thing to remember is that Threads is a new social media platform with a similar function to Twitter. Threads allow you to post and share texts, pictures, and videos. While it is connected to Instagram, it is more about interaction and connection than Instagram.
Thread Reshares mean that other Threads users get to share your text, Image, or videos as you upload them. Most times, when other Threads users share your posts, people from different timelines get to see your account and content. It is one of the best ways to increase your visibility and presence on the platform.