We met online.?

Ok I'm going to guess you guys met on a dating site right?

Likely what happened is you guys connected online, the date went OK, but he was meeting other girls as well and found someone else who he feels he has a lot of commonality with.

He gave you a shot, and he moved on!

Really, it doesn't matter. He obviously didn't get what he was looking for, and he left it on a positive note. Best thing you can do is just realize he wasn't ready for more like you were

Because he wasn't feeling it like you thought he was.

Maybe he’s waiting for you to ask him out.

Maybe he thought that you two wouldn't work long term