If you're already using a compression algorithm--like gzip--with your website, optimizing your html tags can lead to smaller compressed page sizes. One thing that compression algorithms do is search for patterns. Larger and more frequent patterns compress more. By putting html tag attributes in the same order all the time and using the same quote style, pages can be compressed more leading to less bandwidth being used and quicker load times.
Here are some examples:
Original 1: <a href='http://test.com' title='test' class='test'>test</a>
Original 2: <a title='test' href='http://test.com' class='test'>test</a>
Both become: <a class='test' href='http://test.com' title='test'>test</a>
Original: <a class='test' href="http://test.com" title='test'>test</a>
Original 2: <a class="test" href='http://test.com' title="test">test</a>
Both become: <a class="test" href="http://test.com" title="test">test</a>