They got a lot of press (at least in the US) for their innovative procurement robots... that's how a lot of kidless American geeks found out about their success.
If that's their company name ( http://www.diapers.com/aboutus/aboutus.aspx ), that's their company name. Take it up with diapers.com (the company, not the domain name) if it's confusing. For the record, I agree with you, but a bunch of parenthesized "we mean the company, not just the domain name" seems superfluous given that the rest of the article is a click away.
Maybe I shouldn't go so far as to say what others should know, but I don't have kids either and I'm aware of Diapers.com, and I'm more developer than business man (or at least I suck at being a business man).
I certainly don't think the title is sensationalist, but for the sake of clarity (given the up/down votes of complaints such as yours) perhaps it should have been made more clear that a company was purchased and not a domain name. On the other hand, would there be any confusion if it was Zappos.com?
The headline makes it sound like they bought the domain name for that figure, which is sensationalist and inaccurate.