Photo credit: AndreasG

1. Zoho Notebook: Web-based application allows you to write notes and documents and to edit them in real time with other people
2. TagandFile: Web-based tool lets you store files online and share them with other people
3. Shadows: Online service allows you to annotate web sites and to share your modified version with other people who can further edit them
4. Kool IM: Web-based IM service lets you access multiple messengers accounts without registration

1. Zoho Notebook
   
   Zoho Notebook is a web-based application that allows you to write notes with text, images, audio, video and HTML content. After you create and save a note, you can share it with other people, granting them the ability to read or edit your note in real time. People editing the same document can also chat with other viewers to share opinions and comments. To use it, you just need a free Zoho ID.
   http://notebook.zoho.com/





2. TagandFile
   
   TagandFile is a web-based tool that allows you to store files online and share them with other people. You can upload and tag any file you want and, when you upload a new version of a file, all the previous versions are kept to avoid losing any work. You can share and give access to your files directly with people who are signed up to TagandFile, or with others via their email address. Free.
   http://www.tagandfile.com/





3. Shadows
   
   Shadows is both a social bookmarking destination where users can share their favorite web content, and a means of annotating websites via their 'shadow pages'. A shadow page is accessed by clicking on the Shadows bookmarklet when visiting any website. This opens up an alternative, shadow version of the same website, on which users can share tags, discussions and ratings left by themselves, their Shadows friends, and with the entire Shadows community. It is then possible to access all of your personally bookmarked pages from your Shadows profile, in addition to being able to browse other users submissions. Free.
   http://www.shadows.com





4. Kool IM
   
   Kool IM is a web-based IM service that aggregates multiple messengers on one page - AIM, Windows Live Messenger, Yahoo! Messenger, Google Talk, ICQ and Jabber. Registered users can take advantage of managing their accounts and more. However, registration is not mandatory. Free to use.
   http://www.koolim.com