This will make customisation of sites easier. Currently, the following image is used: Triangle
This uses only HTML and CSS and is supported by all "current" browsers (including IE6.0!)
http://www.filamentgroup.com/lab/image_free_css_tooltip_pointers_a_use_for_polygonal_css/
Screenshots from different browsers:
http://browsershots.org/http://tantek.com/CSS/Examples/polygons.html