In my experience working with Notes over many years, it was a neat architecture let down by client UI that did not meet the expectations of users who also used, for example, MS Office apps. Often, they were cosmetic things. But Notes enabled workflow applications like email on steroids; Microsoft leveraged all it could to displace Notes with Exchange and SharePoint, both IMO technically not as good as Notes in many areas, but the Outlook UI was much better than the Notes client for email, and together with the marketing push, client-side Notes was finished. Domino could perhaps have survived, but it needed more than the anaemic LotusScript and formula language to get support from developers, and that never happened.