As you know, you've always been able to download the entrant data from a number of reports or the event data feed, however this data has always been event specific. So if you wanted to send everyone an Christmas Card that registered for a regatta in the past year, you had to aggregate the data from several events, and then "clean" the data to remove duplicates.
We've added another club level applet that will allow you to create a registrant data file from all you events within a user selectable date range. This file looks for duplicates based on First Name, Last Name and Email. So if someone registers with their G-mail address one time and their work email the next time, they will be counted as 2 entries. So it's not perfect, but it should cut down on the time required to build your mailing or email list.