Information Bubbles are small 'pockets' full of information about a certain reality, there are in fact, an infinite amount of information bubbles for all infinite realities, if enough of them group together (Enough to detail every existing reality) then a Metareality Hub will be born, though, such a process is so unlikely the only places that Metareality Hub's have been spotted with these bubbles is in the center of a Metareality Link.
Information Bubbles can also be found in the center of a reality, which is actually the thing that keeps them stable. This is to to with why The Null is like what it is; it lacks an Information Bubble, making it an empty, 'nothing' like void.