It is tough to limit choices to 10 tools, but here is the list I submitted based on what we have been using inside my company, and what I have been using personally for informal learning, development and collaboration.
- Microsoft SharePoint - we have been using this to create learning environments around formal courses to enable informal learning - includes wikis, shared calendars, document repository and many other joyful tools!
- Yammer - our enterprise microblogging tool has provided a venue for groups to form and learn from each other. Informal learning, collaboration, social learning, sharing - it all happens here.
- Microsoft Office Communicator - share your desktop and video conference using voice over IP in an instant.
- Delicious - my personal knowledge management favorite.
- Skype - bringing people together - even when they're not!
- YouTube - when you want to make a point clear to people, you can usually find a brief video to share that does it for you.
- Dropbox - new to me and moving up the list. With the growth of tablets, this tool becomes more important for sharing.
- SlideShare - great for researching presentations and sharing your own
- Twitter - I've learned more through the connections I've made through twitter over the last two years than through any other means.
- Ted Talks - If you haven't seen one, check them out.
If I could have added two more I would have added Evernote, and of course, Blogger.