I am slightly under-whelmed by Rollyo, but I think that's because I don't need to do a lot of research. I can see why Arianna Huffington finds it useful (she's one of two noted on the site -- the other is someone with shopping sites,) but for me, it's nothing I really need.
In terms of a library use, it would seem to be a shortened version of the Librarian's Internet Index which many libraries have links to. I suppose a library's staffers could use Rollyo to create links to sites on narrow topics, to assist users. Such a project, of course, raises questions over the criteria for inclusion/exclusion. Maybe websites could be added to books for the Banned Books Week observed by many libraries.
23 Things #12