Email size limits
Most email administrators require attachments to be below a certain size. Unfortunately, for the user, this can cause all sorts of headache when they need to send a document that is larger than this. For instance, Google has a standard 25 megabyte (MB) limit, which allows the vast majority of emails, but blocks the most problematic. I've used 25 MB as a limit before.
A user sent a very large, 1024 MB (1 gigabyte (GB)) video file via email to eight people, four of which were other users within the email system, four of which were external to four organizations.
For the four internal emails, they all got delivered. However, the email is duplicated four times on the server, then cached on each of their personal devices. So the 1 GB email now is taking at least 8 GB of your organizations resources, plus it took the bandwidth to download the email, restricting email access
For the four external emails, two of them got blocked, as the external server had a restriction that blocked the delivery of the email.
Two of them got delivered, but it required your mail service to use bandwidth to each of their servers to deliver the file, then at least 2 GB of each of the external service's storage space, and the bandwidth to deliver to their devices.
All in all, the one email used at least 12 GB of storage space, 8 GB of bandwidth, and wasn't delivered to two of the eight recipients. This is also ignoring document retention policies, which means that this space could easily be stored for years after the original email has been deleted.
Scaling this to entire organziations result in problems managing storage space and bandwidth, as both the number of users, and often recipients per email, goes up.
A very simple solution is to email a link to a shared resource. This could be a link to a web server, file server, sharepoint, or other collaboration space that both the sender and recipient has access to.
Many media companies will maintain an FTP (File Transfer Protocol) server, that allows external clients to share very large files with them. They're used to working with large files, so this provides an industry standard, yet antiquated, way of dealing with this problem.
Dropbox has also become a very popular resource for sharing files between small groups, as it allows the contents folder to be shared between devices without any real work done by the user.
If the amount of data is large, time is short, and you are geograpically close, there's usually the possibility of handing someone a thumb drive, too.
Of course, this is all assuming that the data isn't confidential. Since we started with email, which is unsecure by nature, this is a good assumption. Email security is another article.