Email notifications have not been working for me for the last week or two.
When I left a comment on a sentence and others responded no response come through to me. For a while I thought no-one was responding then I cam across a comment with a response. I checked my settings which were fine and posted this comment.
This morning it started working again.
It is not at present possible to check the comments you have made (the 'stream' is just that and like Old Father Thames it bears all its sons away) so I could not look back systematically. Here's a feature request. Select messages by author and date posted.
I too feel there might be a problem here. I follow a number of discussions either by directly contributing to them myself or by clicking the button "Follow discussion."
On several occasions I have gone back into a discussion forum and found comments left by other users that were not e-mailed to me. I reported it but the reply seemed to indicate there was no problem at your end so I just assumed there was some other explanation, although still a little perplexed!