I personally agree with using light boxes, IF they are done right. If the connection speed and browser can easily handle it, why not? But still always having the permalink "/sign-up" (or whatever it is) so you can link to it.
Can you provide more insight on why you are against that? Just curious if I missed the boat on people hating light boxes now? haha
There's usually no indication within the content that what you're clicking on, usually a link, is in fact not going to take you to a separate URL where you can complete your business, which is conventional, but it in fact going to change your visual experience by [poorly] applying an opaque [non-universal] overlay to your content and present you with a form, content, media in a format that is completely unnecessary to the experience. In the case of the author's preferred third-party plugin, it adds an additional four steps to your experience:
1) activate overlay, 2) resize viewport to content, 3) present content, 4) user-activate close button.
All for content that is preloaded with the page. The author seriously thinks that inconveniencing the user with added steps and amateurish functionality at the moment of conversion is a good idea, but you can browse the code over at their webpage to get a feel for what they think is acceptable advice.
The author-suggested solution takes four to five times longer without even making a server call. If that isn't ignorant, I don't know what is.