I’m fairly new to OSM and would like to know why there is no mouseover effect on POIs, showing all in the info linked to it. (Or am I just to stupid to find it?)
Yes I know you can switch to data mode and then click a point, but first you have to switch off areas and than even not all POIs or symbols in the Map are cklickable.
The legend is also not very helpful when there is a symbol POI you don’t understand.
From the browser’s perspective, the map on osm.org consists only of images like this one: There is no vector data or semantic information attached to it, POI and labels are just colourful pixels like all the others.
Of course it is still possible to build a map from OSM data with clickable POI. For example, http://openstreetmap.ru/ has clickable POI with markers and a mouseover effect. (It works a bit differently from osm.org though - you have to select a POI category first. And of course it’s in Russian.) I’m even currently working on a map with clickable POI for a regional wiki myself.
However, doing this on a global scale, with good performance and working in all browsers is a technological challenge. If a developer were to build it, it would most likely find its way onto osm.org quickly. “Clickable POIs on the frontpage” are even listed as a Top Ten Task, but although there are a few prototypes, nobody has built a final solution yet.