Yeah, and now you can't respond to anything he says. You've had your voice taken away. The only way back into the conversation is to create a new Twitter account (in violation of the Twitter TOS).

And if you log back in with the blocked account, and try to tweet @realDonaldTrump, it will prevent you from posting because he blocked you, preventing you from using his Twitter handle in any way.

You also cannot retweet him anymore, which is a common way of publicly condemning the things he says.

In the hands of the President, the block feature is a powerful censorship tool.