Most common Serif fonts are Georgia and Droid Serif. In typography, serifs are semi-structural details on the ends of some of the strokes that make up letters and symbols. A typeface with serifs is called a serif typeface (According to Wikipedia). Serif fonts are easier to read. This is the reason that serif fonts are quite popular on printed work.
Serif fonts are also commonly used for headings. To make your blog posts more readable to eyes, you can also consider using serif fonts. For your help, here are 25 beautiful hand picked serif fonts that are free for personal use but may or may not be free for commercial use. Before using these fonts for commercial use, you must check the license of respective fonts.
FHA Modernized Ideal ClassicNC