This program comes as an alternative to using Mac's Contacts application for managing details about the people you know or work with. BusyContacts is more feature-rich than Mac's default utility, allows you to sync the stored information among your media devices and social media accounts, and lets you import and export contact details with ease.
You can store various types of information about your contacts, from name and email account to home address and birthday date. The program also displays a chronological listing of all of the activities that are associated with the selected contact, such as to-dos, meetings, messages, etc.
Another great thing is that the program displays a list of all activities associated with the selected contact, such as to-dos or calendar events that you shared with the person in question.
A disadvantage is the fact that BusyContacts supports only one output format when exporting your entire address book or contact info (VCF).
Even though you can easily find cheaper solutions for managing your contact details, they don't provide you with as many features as BusyContacts offer you. It's up to you to decide, based on your needs, if it's worth buying the program for your Mac or not.