In reply to Nils.

Thanks Nils! Yes, I've been been using Diigo--apparently since 2 June 2015. I'll agree it is very nice, but, like most social sites, I don't expect it to be around forever or to really safeguard my data. Thus, in IndieWeb POSSE or PESOS fashion, I tend to keep my bookmarks and annotations (as well as other social data) on my own website and syndicate them out to other services like Diigo. I often back up/cache site data to my own site's back end and frequently also regularly archive it to the Internet Archive as it's posted.

While there are a few social features in Diigo including RSS feeds, I do wish they allowed following/followers so that I could more easily subscribe to other's content in a simpler fashion. I suppose I'm content enough to follow people or topics/tags (example: edtech) in my lowly feed reader.