We have just moved to a new server, and we see that hotmail and att (and maybe some others we haven't found yet), are blocking email from us.
Our new server IP does not appear to be on any blacklists so it may just be they are blocking the server because it's new to them or it is similar to an ip they don't like or they are just being grumpy.
We expect to have it sorted out very soon, but if you try to register an account at the forum or otherwise expect mail from us and don't see, that's why.
I'll post an update here when we see that the emails are going through.
Note that we can still receive mail FROM you, it's just if we send email to your address you won't get it. So you can still submit comments to us from our Contact