My research and my experience have taught me that agents love love LOVE authors that engage in self-promotion. Their primary goal is to sell books and make money, especially if they pay you an advance.
My experience has also taught me that doing it too early and too often isn't a good idea. You don't have to worry about sharing too much world and information; you have to worry about inundating your fans every single day with content and info from your book.
Even if the goal is to promote your novel I'd spread the information out as much as possible--say one major thing about the book a week. I wouldn't start too soon--don't start before you have a solid release date. Nothing is more aggravating that people that promote something that isn't available or has no date of availability. Lastly, I'd find related information to post every once in a while when you're not posting any of your book's information. Say your world has a lot to do about mountains--then post related information about mountains.
For a better example, one of the world's in my book deals with swords and horses. So to get people caught up with the terminology, I'd post and make videos about horseback riding and sword making. Now, when the reader comes across the word, 'quenchant' they will know what I'm talking about.