It's a question I've come across a few times recently: We provide a number of ways for you to store documents online:

1. Windows Live SkyDrive gives you 5GB of storage for free
2. Office Live Workspace gives you a further 500MB of free storage
3. Live Mesh gives you yet another free 5GB
4. Hotmail gives you...yet another free 5GB

And there may be a few I've missed.

So with all this free storage, what's the best way to use it? Here's my totally unofficial guidance:

1. SkyDrive is a great place for storing finished documents, or documents that are used for reference. It's great for sharing with others but isn't really about collaborating. Generally you can view SkyDrive as a USB drive on the Internet, but that's much easier to share with others
   
2. Office Live Workspace is for collaboration rather than storage. So this is where you can build a document with input from others, allowing them to comment and suggest changes. Once you have finalised the document you should probably move it to SkyDrive and share it that way, freeing up space on your Workspace for the next project.
   
3. Live Mesh is focused on having your files available everywhere you need them, on any device or on the web. It can of course be used to share files with others too, but isn't really about collaboration to the same extent as Office Live Workspace.
   
4. Hotmail is, of course, all about email in terms of storage. I use it to keep copies of emails that are important to me (such as receipts for purchases) that I drag to a folder called "retained documents".

I'm not saying this is the only way, but it works for me. So if you want other people to collaborate with you on a project, Office Live Workspace is your best bet. For pure storage for files that you either need to keep to yourself or share, choose SkyDrive. If you need to have easy access to documents from any device, Mesh is the way to go. And for email storage the ideal option is Hotmail.