The same results can be achieved by a lot of people using their mouse and keyboards.
You'll need a LOT of emails. There is an open secret known by savvy politicians, Newspaper editors, and other people who deal with public opinions, and that is that e-mails are not as effective as people think.
Phone calls are a bit more effective, but the impact is more transitory. Once the phone stops "ringing off the hook", the effect diminishes.
Back in ancient times, when people actually wrote and mailed letters the politician, editors, etc., paid attention to them, and the volume of them, because they realized that for each person who took the time and effort to write and mail each letter, there were dozens to hundreds of people who felt the same way, (and would vote) but didn't make the effort to send a letter.
Handwritten letters were given more weight than form letters, as well. Same idea. Plus, there is the physical volume of letters. They take up space. And, they need to be stored, or disposed of, both of which require work and cost by the staff. This makes an impression that emails cannot.
Remember the key thing that decided the case of Santa Claus in
Miracle on 34th Street? It wasn't the lawyer saying there were hundreds or thousands of letters, it was the physical paper burying the judge (who had demanded they be put on his desk..
).
A million emails means you got a lot of people to make a couple mouseclicks. AND they all fit on your phone. The number is impressive, as a number, but its only a number, not a huge, unavoidable, constant physical presence.
Don't get me wrong, I'm not saying emails aren't effective, what I'm saying is that those things that take more effort than clicking a mouse have a greater impact on those we wish to reach. A dozen people willing to stand in the cold and rain, waving banners means people committed to enduring hardship to get their message across. They may only be the tip of the iceberg, but they are proof the iceberg is there, and should not be ignored.