Facebook Domain blocked

Sorry,to be a pleb. but I don't know!

Here the link again, which shows if you're using the Internet Guide.

I sent at least a dozen messages (there were no replies)to the Administrator on the Domain Blocked notice.

Then this blocking was not related to DynDNS. Their block pages do not come along with an option to contact a network admin, not that I knew. It must have been another service.

I installed the DynDNS updater-should I uninstall it?

Depends on why you would use it. You only need it:

1. if you want to reach your network from outside with a DynDNS hostname,
2. if you need to know the current IP address of your network from outside,
3. if you use the Internet Guide in conjunction with a defense plan.

And a note what may have happened why some sites were blocked for you:
There are services like the Internet Guide where personal settings are bound to the public IP address of a user. If this user doesn't keep the dynamic IP address information updated at the DNS service, another human using the same DNS service may inherit this IP address. From this moment on this other user (you in this case) uses these settings, which are not his/her settings. There is no easy way to escape except with trying to get another IP address while disconnecting from and reconnecting to the internet, or by using another recursive DNS service.

Is your computer using the Internet Guide?

So, why did you post here then? What made you think that DynDNS is involved? Did you recently install the DynDNS updater?