he dropdown menu is very SEO friendly. The Son of Suckerfish method which this plugin uses is pretty much the king of SEO friendly dropdown navigation.
From a search engines perspective, these dropdown menus aren’t terribly dissimilar from the average WordPress sidebar, albeit many sidebars feature heading tags which may offer a little (negligible?) SEO benefits.
The plugin does use Javascript, but that has no effect on the SEO properties of the menu, as it is only used to trigger the dropdowns in very old browsers like IE6. I also put the Javascript into IE conditional comments so that only those old browsers even need to bother downloading the teeny bit of Javascript that they need.
I’ve been looking at ways to add more Javascript features to the dropdown this evening, including fancy graphical effects like fading, delays etc. But none of these new features (which would be optional) would have any effect on the SEO friendliness of the menu either as they are simply additions to the existing unordered list which contains the menu options.