Both Delicious and Diigo are bookmarking tools. You probably use your web browser (IE, Firefox, chrome) to do the bookmarking for you. You probably have a long list of bookmarks or maybe you created some folders at an attempt to organize them. Remember that awesome idea on graphing quadratic functions you found? I bet you can not find the bookmark within five minutes. With Delicious or Diigo, you could have found it within five seconds. You use a bookmarking tool to obviously bookmark instead of using your browser. When you bookmark a page, you can add a sentence or two or three description to it. How many bookmarks do you have in your list you have no clue what they are for? You also "tag" your bookmark with a keyword or words. To use the graphing quadratic functions idea, I would have tagged using "graph". "quadratic", "function". Diigo will also suggest tags to you based on what other people have used. Later when I want to search my bookmarks I can search by tag. First I can click on the tag "graph". Any bookmark with graph as a tag shows up. Then I click on quadratic. Any bookmark with graph AND quadratic shows up. You can choose your tags in any order. No more remember what folder you put it in. You can also search your bookmarks similar to how you would search using Google. Another benefit to a bookmarking tool is you can search someone else's bookmarks if they made them public. If a person took the time to bookmark a page it must good or you can do what you normally do and search using Google and have to shift through thousands of pages. I switched to Diigo along with many others when it was leaked that Yahoo was looking to get rid of Delicious. I actually like Diigo better. I recently had all 6-12 math teachers in our district create an account and join a group in Diigo. Now when any of us bookmark a page, we can share it to our group.
Seesmic Web/Twitter - free
I know what you are thinking. "Why would I want to read about someone's life? Like I care if they just farted in line at the store." Twitter can be much more. I have met wonderful teachers who are willing to share anything they have as well as help you think through those random ideas you get for a lesson. A teacher on Twitter created an applet for me to use in stats. I am currently doing a book chat with a few teachers on twitter (search for #sbarbook on Twitter). I have gotten more out of Twitter than most professional development sessions (except for the math PD at Oakland Schools. Those have helped shape my teaching for the better). Instead of using the actual twitter site I wanted something to use on my computer and Droid. I also did not want to install anything on my computer. I wanted to be able to log in using any computer and get the same experience (set up). It was hard to make the choice. There are some good options out there and each has its own pros/cons. I am using the Seesmic App for Droid and Seesmic Web whenever I am at a computer.
LibraryThing - free/$
Ever read a book and about half way through realize that nagging thought in the back of your head was right? You did read this book before. This is another tool where there are many options. I settled on LibraryThing mainly because you get the feeling the owners built this site because they love books, not because they want to make a million dollars. A free account lets you add a certain number of books. You can get a lifetime account for $25. Yes I said lifetime. Any book I have ever read or owned is recorded here, since I signed up that is. Just how many Hardy Boys did I read back in the day? You can look at your books as a list or by covers. You can organize them anyway you want. There is a community forum, book give aways, author chats. You can see recommendations based on what you have in your collection. I also use it to keep track of my kids' books.
Hopefully I was able to help someone out with an idea to make their life easier. Feel free to contact me with questions. I only charge $40 an hour per tech support call, or I like cookies.