Deportation is a different legal event. It's a forceful expulsion which occurs because you did something seriously negative like break the law. Deportations are a big deal and a bad thing to have on your record in any country when it comes to your future prospects with that country.
To use a super rough analogy it's kind of like an honorable vs dishonorable discharge from the military.
In practice, the immigration authorities have enforcement priorities, and deporting overstating H1B is very far from being one.
As long as you don't cross a border, no one will come looking for you.
Source, my immigration lawyer when I was in danger of overstaying my H1B.