You cannot request data using API keys. You would have to scrape the data (threads, mentioned posts, etc.) manually and work on that. For PMs, that's not doable unless you make the user run an extension or his own script locally to get those information's.
Ofc I can't get pm's and all, but the API key will be like
ana limited/controlled access permission without putting your sensitive credentials, you know what I mean
.
I've thought about scraping, but the information gotten will be very limited