Serifs are small lines at the end of characters. Most popular Sans Sefir fonts are Helvetica, Avant Garde, Arial, and Geneva. Serif fonts include Times Roman, Courier, New Century Schoolbook, and Palatino.
Left A is Serif and right A is Sans serif. If you click on the picture, it will lead you to an amazing infographic about Serif vs Sans: The Final Battle from urbanfonts.
According to many studies, Serif fonts are best to use in print, and Sans Serif in web.
We made a list of 10 beautiful free Sans Serif fonts from the web.
Keep in mind, not all are free for commercial use. Enjoy!