No there is no labeling capability at this time. It's a good idea though.
Thanks,
Mike
You can manually add labels to an ArcGIS web map by drawing them on. You simply type in the text, so it isn't the same as feature labeling you are asking for, and the text doesn't scale with the map (so it remains the same size as you zoom in and out) but it might be a useful alternative. To add text labels to an ArcGIS web map, open your map in ArcGIS Explorer Online, choose Add Features, and you'll see a Text option under Map Notes.
You can manually add labels to an ArcGIS web map by drawing them on. You simply type in the text, so it isn't the same as feature labeling you are asking for, and the text doesn't scale with the map (so it remains the same size as you zoom in and out) but it might be a useful alternative. To add text labels to an ArcGIS web map, open your map in ArcGIS Explorer Online, choose Add Features, and you'll see a Text option under Map Notes.