I like using WeTransfer to transfer things that don't fit in emails, mainly because the site is fast, has a large upload limit (2GB!) and is easy to use (no registrations required!). It seems like their main business model involves showing advertisements in the background picture of the page. This spot makes a lot of sense due to the fact that people are likely going to keep the page open for at least a few seconds as they upload/download things.
However, a particular advertisement that I saw recently caught my eye (click on the image to make it bigger):
Pretty clever way of getting people to apply I must say!