Why are there extra spaces in my blog post?

The reason is simple: You likely have pasted from Word or another text editor that introduced extra spaces. But it's very easy to fix, and you should fix it.

To fix go to your post and select the "Text" tab. Scroll to the area where you have extra spacing and you will see this group of characters:  

That stands for "Non-Breaking Space." Delete those, update your post and your extra spaces will disappear.