To avoid possible misunderstandings: I'm just a Diigo user, with a non-paying account.
Diigo is primarily for bookmarking, and as such, it works great. The page-saving is just a side option in Diigo, and if you want to do that systematically, there are dedicated web applications for that - e.g. http://webcitation.org .
As to saving in one go more than one page of a site, there could be serious copyright issues with that, not to mention storage.
As to the legality of the business deal between Furl and Diigo: unless you are a shareholder (and perhaps not even then), it's not a user's concern: if you choose to use any commercial non-paying non-free web application, you just have to accept the risks inherent with such a choice, and see for yourself how to limit them, e.g. by making sure you can back up your content.
As to "they should have started their own site": Diigo bought Furl in 2009, but it was launched in 2006.
if I view without being signed in the http://www.diigo.com/list/calmansi/unesco-wh-accessibility public list I made, only what I have highlighted in the pages appears as annotation. The related sticky notes don't show, even though I made them public.
Is there a work-around for that, other than retagging all the entries in the list and sharing the link for that tag page (where the sticky notes seem viewable without being signed in), instead of the list?
thanks, Graham: I've enabled notifications for the thread you mention. And meanwhile I've added a unescowhtext tag to - and only to - the items in my list: the resulting http://www.diigo.com/user/calmansi/unescowhtext seems to work fine when not signed in