Harvard will be sending out decisions on March 21. Does anybody know how decisions will be communicated? Although I had heard that they email decisions, I think they told me that they will send decisions by regular mail, though they were not very clear: does anyone have any info on this (since regular mail means we will hear much after the 21st)? Thanks.

I suggest you read the following blog: http://www.llm-guide.com/board/41265/3
all your questions will be answered....

Some one wrote to Harvard and informed Harvard their other admission offers and deadlines, an admission staff later called him to inform the admission offer. Therefore, it seems that Harvard has already released some admission offer in an informal way.