I sent a Valentine's Day greeting to a man, but he didn't reply. What does this mean?

There may be many reasons why he doesn't reply to your blessing message. Here are some possible reasons:

1. He may not see your information: Sometimes, a man may miss your information for various reasons, such as being busy, distracted or just not seeing it.

2. He may not know how to reply: Some men may be shy or not good at expressing their feelings, so they may not know how to reply to your blessing message.

3. He may not want to reply: Sometimes, men may not want to reply to your blessing message, for example, because they don't want you to expect anything from them, or because they don't want to have any contact with you.

Whatever the reason, it is best not to over-interpret his behavior. If you want to keep in touch with him, you can try to contact him later to see if he is interested in you.