The arrow at the first result indicates the keyboard shortcut functionality. Now you can navigate results without mouse: use up/down keys to select a result, then press enter. I love that feature!
I really don't like the blue arrows... All this does is keep the page from going "below the fold" (a $$ decision?). I use the keyboard to browse, and I expect the down arrow to move the page lower to reveal results 5-10.
* If you are logged in, you can turn these arrows off by disabling Google Instant.
* You can also toggle this functionality by pressing tab