Diigo: I created a Diigo account a couple years ago, and I've got a nice Diigo extension installed in Chrome which makes it really easy to bookmark things quickly and easily on the fly. The place I most often find content I want to share with my students is Google+, so I make sure to bookmark with Diigo anything I want to find again later. Google+ is great, but its search features are really (REALLY) bad. If I don't bookmark stuff I want to use later, the odds of ever finding it there again are low. When I want to share something with my students, I bookmark it with the Diigo tag "announcements."
Class Content Blog: As I've explained before, I have a big class content blog where I keep things I want to share with my students; I use a blog for that because it is fast and easy to manage. So, periodically I write up the content that I have bookmarked in Diigo, backdating the posts so that they are available for me to link to at any time. To make that easier, I use various blog labels to keep track of these posts. So, for example, I have a series of posts labeled "writing tips," etc. I use a blog like this in order to provide some commentary to help the students see just why I am sharing these items with them, how they connect up with the work they are doing in class, etc.
From Diigo to Blog: So here's the trick I use to make this process work. I tag things in Diigo as "announcements" that need to go into the class announcements blog, and when I have written up the blog post, I add the tag "blogged." To find out what I have not blogged yet, all I have to do is search my Diigo bookmarks for "announcements NOT blogged" and I can see right away what's I might want to write up that I have not written up yet. I always have more resources available than I can keep up with, and Diigo patiently keeps track of all of that for me.
I use the same process for the "Tech Tips" that I create for the students; these are actual extra credit assignments so they are part of my class wiki rather than the class announcements blog. So, as I learn about free browser-based tools that I might want to recommend to my students, I bookmark them in Diigo with the tag "techtip" and then I review them in detail later, deciding which ones to recommend to my students. That is a more time-consuming process, and I usually only have time to create new tech tips over winter break or summer break. Diigo is very patient, though - those items tagged "techtip" can sit and wait until I am able to get to them.
The "announcements" items, on the other hand, are quick to write up as blog posts, so that are something I work on periodically during the semester - in fact, I will probably do some today because it is a fun and easy task.
I used to be a very dedicated Delicious user and it was really hard for me to get used to using another service. Even though Diigo is a lot like Delicious, it took me several tries to really get into the habit of using it, but now I use it for lots of different purposes and projects; I'll try to write up some blog posts later about other ways I am using Diigo.
Meanwhile, I cannot imagine trying to manage useful class resources without a tool like this, and one of my resolutions for next year is to find even more/better ways to take advantage of what Diigo has to offer!