Well developing websites is something absolutely different than domaining. It's website developing. Domaining means buying/selling/parking pure domain names. It has nothing to do with content.
though it may seem contrary:
in a way, i can understand the comment made above
as, "website developers" in a group by themselves, typically are not in the same group as your average domainer.
though for sure there are web developers who are also domainers and vice versa, but it's more likely that the majority of those who do one or the other, don't do both.
domaining as an adjective, basically does describe the buying and re-selling of domain names, along with the proceses and transactions involved.
all of the peripherals like, establishing and usage of parking services, creating drop catching/api software sites/lists and services, creating the bot, the agg, the blogs, the conventions, the auctions, creating domain management software, affiliate programs, mini-sites, adword/arbitrage, website development, adsense implementation,etc, etc..... all represent the growth of individual or groups of domainers, which in turn grew a market for domain related business.
as domaining grew, folks saw the needs and set out to fill them. thus making profitable businesses for themselves, while providing tools and services for others to profit from as well.
"domaining is not going to it's end, it's going thru an evolution."
imo...