Haha, I'm not really sure what you mean. Yesterday I didn't know TogetherJS was ready to use, and yesterday I didn't know of Mozilla's plan to not support IE.

How could anyone be bothered by something before they know about it?

Today, IE users are not using TogetherJS. And if TogetherJS doesn't get it's act together they won't be using it tomorrow either. I have four browsers installed on my computer and everything I develop has to work on all four; one of them happens to be IE 10.