Sipping from the fire hose that is the Web gets harder every day because of the amount of information that is available. You probably have your own methods of filtering or curating the Web for yourself. Perhaps, following this blog and others is one of those ways that you use other "trusted" sources to do some filtering for you.
I find that even on a site like twitter, where the messages are short or abbreviated, I follow about 400 people. If I leave my twitter page open and unobserved or a an hour, there will be about a hundred posts. That's more than I have time to sift through or read. One thing I do is create lists on twitter so that I can focus my attention on a topic. When I look at my public list for educational technology, I am seeing 90 people, and my list for environmental tweets only has 25. That makes it more manageable. If you trust my curation, you can follow my public lists. (I also use private lists for my family and friends.)
There are many sites where people intentionally curate the web around topics and save that information both for themselves and for others to use. David Kapuler collected some sites (his blog is cyber-kap.blogspot.com) that I use, and others that are new to me.
Some of these sites could certainly be used by teachers to filter the web for their students and for certain assignments. Pinterest - coming on strong, this site offers a way of curating the visual web by pinning images on a virtual bulletin board. My own experiment with Pinterest is to try using it just for the poetry side of my life http://pinterest.com/poetsonline/ Teachers can easily use Pinterest or other sites here to create a curated list for an author, topic etc.
Bag the Web has you put things into "bags" which you can embed into a site
MentorMob lets you create "playlists" that can contain different types of media such as video, articles, pictures, etc. Once these playlists are created, they can be rated and shared with others.
List.ly creates an interactive list that others can commenton and vote on.
Middlespot takes another approach where you can browse the web and stick sites onto a "dashboard," which can be edited and shared with others. (This site also has a paid account.)
Paper.li is a site I have used for awhile to publish an online "newspaper" from your own web content (twitter feed etc.). It's a kind of meta-curation since it further filters things like twitter which I have already filtered by lists. It automatically creates your newspaper and updates it on a scheduled basis. (It does not archive/save issues.) I have created one with my general interests http://paper.li/ronkowitz and another focused on poetry and writing http://paper.li/poetsonline The application also pushes a notice to twitter and Facebook when my daily issue is published.
Similar sites that I have not used are Searcheeze for text, video, images, articles turned into a digital magazine and Scoop.it which turns social media into a digital magazine.