No, those are general-any link posting. This is more like Planet Mozilla, which used to be maintained as a curated aggregator of the personal blogs of contributors to the Mozilla project, which was not filtered exclusively to their Mozilla-content posts. Bubbles accretes on a different criteria than that, but at its core is similarly centered first around ‘curated authors’ rather than ‘curated links’, and then second around publishing all posts by a curated author. That curation is what makes it more valuable than a generic-any site aggregator like Digg or HN: a post by a curated human is much more likely to be interesting than the majority slop of /new on any content-first aggregation site (Imgur is a great example of this!).