Looks like a borderline case to me, because
a) It's not at all clear to me that http://portal.wikinerds.org/node/103 adds much to the http://en.wikipedia.org/Homo_floriensis article
b) Even if it does, it's not clear that the Wikinerds link is the best source, or even a particularly good source for that information. It is not nearly as close to the source, or as authoritative as several of the other links that are already in the article.
c) NSK does have a clear promotional interest in wanting to build up his site.
There is such a thing outright gross spamming. I don't think NSK is doing this. In the email world, outright gross spammers are the people who simply pump the stuff out in bulk, more or less acknowledge that it's spam, hang tough, and just defy anyone to stop them. In Wikipedia, it is people who systematically add links as fast they can type (or as fast a Wikipedia's servers can accept them!) There was (for example) a used bookstore site that was planting literally scores of links to the site, one in every article about an author whose books they carried.
NSK isn't doing anything like this.
On the other hand, my perception is that he _is_ seeking to find ways in which he can simultaneously help Wikipedia _and also_ promote his site as a byproduct.
This is skating on thin ice, and NSK should know it.
There's a wide variation in peoples' attitude toward and trigger-happiness with things that are perceived as spam. NSK should not be surprised that some editors are going to delete this kind of link, with varying degrees of politeness.
I don't think there's any need for NSK to "leave Wikipedia" but I don't think he should be too surprised or indignant if links of this kind are removed. A reasonable reaction would be for him to exercise more restraint in adding them, and adding them only when it is clearer that the Wikinerds link _really_ is valuable. NSK should keep the frequently low. Add a note on the talk page justifying the link, because some people will tend to be trigger- happy on anything that looks spammish, even if it really isn't. And if the links get deleted as spam, shrug it off.