Lotus Knows that collaboration means people working together to achieve better more productive results. Sometimes this means participating in finding expertise, sharing files, discussions, instant chats, collaborative applications, workflow, knowledge management and sometimes it means sending an email or scheduling a meeting. Lotus Notes and Domino allows all of these types of collaboration (and more) on a single platform via any client (Rich, Web or Mobile) on any O/S (Windows, Linux, Mac).
Competing solutions require multiple platforms to achieve these capabilities. Why would you want to use one solution to send an email or schedule a meeting but then require a different solution to book a holiday or participate in a collaborative team space? They are all collaboration. Email is the TCP/IP of collaboration and should not be thought of as a different product. (Remember when calendaring was separate from email (cc:Mail and Organiser vs. MS Mail and Schedule+) - would you ever want them separate again? of course not. So why do it with collaboration?
If you agree, vote for this thought on the LotusKnows Ideajam