What does it mean that the man of sin be revealed?

II Thessalonians 2:3 Let no man deceive you by any means: for that day shall not come, except there come a falling away first, and that man of sin be revealed, the son of perdition;

Will he be revealed before the blessed hope?

Who will he be revealed to? to us? to angels? to the world? to himself?

How will he be revealed? by lying signs and wonders? by the whole world going after him? will he simply reveal himself?