I like the arrowed version that DDG uses; I haven't seen that elsewhere (that I can recall) so far. I think the arrows encourage clicking on it to find out what is behind it, and most folks will probably not want or need to access the information behind it anyway. I prefer less text clutter personally. My personal favorite menu indicator is a small triangle in the corner of the screen (that you mouse over to get to the menu), but that is even easier to miss if you aren't expecting it (the triangle needs to be large for touch interfaces but if standardized could be set to be tiny or not graphically displaying for folks who know it is there and have a mouse).

Also, even if not perfect, I would love if sites that use infinite scroll would standardize on something to get to the stuff that is usually in small text at the bottom, and that icon seems as good as anything to me.

Firefox just changed to the three lines menu icon for the main menu so a bunch more people who haven't noticed it before will be forced to figure out what it means.