Personally I don't think that creating another url service would be worth it. This market is over saturated and would require deep pockets to create a successful one. This is one of those markets when people find one they like they stay with it.
I still think it would have been a fun educational site for elements. Something with ajax drag boxes you can drag around and when to elements like h20 and h3n are combined they make?
So by dragging a h20 box over to the h3n box it would reveal what it does.
Then you won the auction so if have a look at what the top 10 url service sites offer and try and improve the wheel. Good luck with your site.