I just checked and all emails are sent properly.
We had this issue in the past when gmail was delaying our emails. Then all of them came at once after few hours. Looks like it's happening again, my last email from SO was at 10:37 and I'm using gmail as well.
So far reports are only from members who use gmail, so it must be the same issue.
Meanwhile, I can recommend checking New content or All activity on the forum. it refreshes automatically.