Sky Drive confuses me....please suggest.

Ever since I got my Office 365 account I have been using Sky Drive. I liked it and wanted to experience something different than Drop Box so I went with it. However, on my Surface Pro when I try to access a file to send with Outlook it gives me a link. What exactly does this do? Will the person on the other end need to have a Sky Drive account? Just last night I finished a report on my desktop, saved it to Sky Drive and this morning from my SP at a breakfast (away from home) I try to access the file and it says, "SkyDrive files can't be downloaded because your PC data drive is full, or your SkyDrive folder is on a system drive that has less than 3GB of space. How exactly can I fix this? Am I supposed to just redirect to my SD card on my surface? Sorry if these are primitive questions...

Hemi79