E-mail is extremely easy to adopt and use, and lends itself very well to certain types of collaboration. When two people are attempting to collaborate asynchronously, e-mail is usually the best solution. It's certainly far less frustrating than phone tag. But once more people are involved, email's utility rapidly degenerates. While the rise of free, open-source solutions makes it tempting to build one's own collaboration tools, on-demand or Software as a Service (SaaS) solutions are the better choice for the majority of users and uses.