Forum posts I think are only notified if you subscribe to them. You can subscribe to individual theads (above the first post in the thread). I’m still (within the last week) receiving notifications in the forums I’m subscribed to so I think at least those are still being sent out.
It’s also possible to subscribe to forums (at the top of the index for each forum), but this probably only relates to the opening post of new threads. New threads default to unsubscribed, so if you don’t subscribe to new threads when you see them, you would progressively get less notifications.
There are additional settings in the user profile (profile > settings > email). My feeling is that these may have stopped. Many times I see a notification about a message when I arrive on site but I don’t recall receiving an email notification recently
If all of the above are “on”, if may help to whitelist @nakedexperiment.com in your mail reader *and* in the settings of your mail host, but spam these days makes up 45% of all emails. As Ed says, many mail hosts try to cope by binning all messages from certain IP addresses instead of moving them to spam. Whitelisting in your mail host *might* (or might not, depending on the mail host) bypass their binning, but whitelisting in your mail reader can only work if the mail host hasn’t binned it first.