Hi,
I think I may have mentioned this a while ago. Topic reply notifications I get from this forum are unsigned so Hotmail treats them as junk mail.
I'm aware that Hotmail treats a lot of things as junk mail, but since there's no From name on those emails, there's no way to add it to a safe list and Hotmail now regards them as highly dangerous, suggesting that the recipient shouldn't open them for fear of some unspecified contagion.
If the forum admin is listening, it would be a good idea to fill in the From name and address.