NatureServe, as I understand it, grew out of a TNC initiative to develop spatial datasets and provide them to researchers on-line. It seems that, throughout their existence, they’ve struggled with presenting conservation content on the internet: who is their audience? How do they get the data they need, and how is it updated? Much like the rest of the web, a lot of these projects try to do too much (“Let’s get researchers to upload all of their spatial data to one place!”), and the effort dies out. The really useful sites are ones that present novel data-sets for specific purposes. If you need a land-cover dataset, it’s much easier to find it at the host institution rather than going through some aggregated site. “One-stop shops” tend not to carry the stock that they promise. Regardless, it’s National Geographic, so the site is definitely beautiful. I hope they push through that nebulous barrier and keep this thing going.

[Edit: Oops! I forgot that NatureServe developed its NatureServe Explorer and InfoNatura, presenting datasets of species ranges in North and South America, which I've used in the past. They are useful -- but, again, not comprehensive.]