Social Bookmarking Tools
These websites allow you to create online bookmarks that you can annotate, tag, share, and sync with your web browser. Further and even more usefully, you can explore the webpages other people have also tagged; for example you can see all the sites tagged with “online” and “pedagogy.” In essence you benefit from the searches already carried out by other people.
You can save info about webpages that then can be used to create bibliography. Takes a little discipline, but a worthwhile research tool.
WorldCat gets its own category because it’s so useful and there’s nothing else like it. As they say themselves:
You can search for popular books, music CDs and videos—all of the physical items you’re used to getting from libraries. You can also discover many new kinds of digital content, such as downloadable audiobooks. You may also find article citations with links to their full text; authoritative research materials, such as documents and photos of local or historic significance; and digital versions of rare items that aren’t available to the public. Because WorldCat libraries serve diverse communities in dozens of countries, resources are available in many languages.
A nice feature is that you can embed a search-box into any web page, so you can put that, for example, into your blog.
Online Document Creation and Collaboration
Google Docs allows you to upload text files, spreadsheets, and presentations and share them with collaborators. You can choose to let those people just read the files, or to edit them as well.
Editing and Sharing Images
Flickr — also helpful for finding Creative Commons or Public Domain licensed images to use in your own work.
Pixlr — Only does editing, but more functionality than Flickr.
Video Editing and Sharing — I don’t have too much experience with this yet, but here is an article reviewing a bunch of tools, with updated info in the comments: “Video Editing 2.0″.
All of these are similar in collecting short status updates (usually about 140 characters) in a timeline. You can also choose to follow other people’s updates, and some of these sites allow you to post or read updates from mobile devices.
Twitter — among the oldest and most robust, Twitter has many ancillary applications that let you post pictures, organize the timeline in different ways, collect info about those you follow or who follow you, and to track conversations or the topics most often discussed.
ping.fm — the main benefit is that you can post here and have that update go to Twitter, Plurk, Facebook, and other sites.
Plurk — It has a cute interface and encourages posting by awarding karma points, but other than that, I don’t think it differs much from Twitter, and it has far fewer related applications.
Social Networking Platforms
Facebook You all know this one, I think!
Ning — Ning is a little different because rather than being one giant network like FB, any person or group can create a social network on it that is open only to members. For example, some professional organizations and conferences have used it to create sites for members or participants.
News, RSS Feed and Other Content Readers
These kinds of applications let you organize content coming from other websites into a single page that updates automatically–for example the latest posts from several blogs or news sites, or the results from searches you have running. It takes a little setup time, but can be very useful as a research tool, or if you are trying to stay abreast of a particular issue.