The catch is some people have their Blogger profile set to No Reply which means I have no way of emailing them. Or if you win a giveaway you can't be contacted. :(
It's easy to change
*Go to your Dashboard
*Select "Edit Profile" ( it's near your little picture)
*Check the box for "Show my Email Address"
If you're worried about getting junk email or weirdos emailing you then I can only speak from my experience and I've never had anything like that, only the nicest, funniest comments from people whose blogs I follow.
Hope this helps.