It means your boiling water is ready.

Ugh, does this mean I don't get my Wednesday afternoon 'How I Work' today?

The person is communicating with you while they are on the go. It is more likely to be "I am responding to this person now because this communication is important." Also, why do you care what device the person is responding to you on? Sounds like your horse is a few hands too tall.

I don't think it says that, it says the opposite: You are so important I stopped what I was doing and replied to you as soon as I could.