What are “unsafe updates” for list items?

Question

In the SharePoint 2010 server-side object model the SPWeb Class has a property "AllowUnsafeUpdates". What are unsafe updates in connection to list item changes? How are they to be delt with in code?

In the MSDN documentation they give an explaination, but it's lacking in depth. Is there a better explaination out there?

Answer 1

For example, it's not safe to make updates and removal on GET requests, because someone may send you a link, you will click and item will be deleted. Thus it's strongly recommended to make updates on POST requests, thus the error is fired. In some cases it's really required to do and AllowUnsafeUpdates is used.

Please see this link and that link for details.