Founder of Airtable here--we did look at Lotus Notes as an interesting historical precedent, though of course we've also invented from scratch in many cases, and being web-based and collaborative by default is a huge wedge for us in terms of adoption virality. I admit I'm too young to have used Lotus Notes but we did buy an old Lotus Notes guidebook, as well as looked up old Infoworld and other magazine articles (Google Books indexes those magazines!) about Notes, dBase, and other products in the genre : ).