Ask HN: What's the most widely used contact management solution?

Depending on your requirements, outsourcing the first version might be the best option. Check out http://www.plaxo.com/api/widget

Outlook works for businesses that have implemented AD and require an internal address book, accessible by all.

MS Access databases or Excel spreadsheets for small businesses that tend not to have AD set up.

Go for CSV to start with.

When I centralized my contact database about a year ago, I pretty much had no viable choice besides Outlook. Most applications have an "export to Outlook" feature and it's at least pretty decent at contact management.

Import from CSV, most contact management tools have an "export to CSV" option.

I second that, plus importing with CSV is incredibly easy for most applications.

Just make sure you have matching fields, for example a first, middle and last name instead of just first/last so it plays well with Outlook.