At this stage I've gotten what after reading this essay sounds like the baby brother of this: the oddly aggressive hire attempt. These companies have been not necessarily direct competitors but people in related spaces who might want to add what I'm doing to their tech portfolio or use its techniques in their products.
The interactions have been quite different from any other "job interview" I've ever had. I've said no three times so far to some version of: "your project is awesome," followed by some interesting discussion, followed by a hiring offer. The hiring offers have been decent but not outstanding, and they've included nothing for the project -- no "acquisition" to go with the hire. When I bring this up, the response is that my baby isn't "worth very much on its own," etc. In one case the response was oddly condescending even in its wording, which was discouraging until I went and read all the users raving about my stuff and then looked at my rather nice looking metrics again. In another case it was explained to me that while my product was interesting, I obviously wasn't... "business" enough? That's not how they put it but that was kind of the implication. I interpreted it as "you're not coming off as alpha male enough to run a business" or some version of that.
In retrospect I saw these as negotiating tactics to shake my confidence in moving forward myself. These folks are trying to get me plus a lot (3 years) of code, users, and momentum without actually paying anything for the latter two things. Looks a lot like the kind of hardball PG is talking about-- I assume "corp dev" offers come in when you're at a bit of a later stage.
Now I've got another one in the pipeline. I've decided the best way to deal with them is to go ahead and chat but otherwise to change nothing about what I am doing, to not spend much time on them, and to constantly remind myself that I am the one interviewing them and deciding whether to accept their offer. At this point given the metrics I'm seeing, the offer would have to be very good.
I'd say that the advice in this essay is probably good advice. If you do have the internal discipline/experience to put these sorts of things in a "maybe but probably not" folder, it might not hurt to chat about it with them, but if you have any doubt or if you're too busy just say no and move on. If my current discussion turns out like the previous ones I will probably do the same moving forward.