When volunteers update their interest forms, it automatically assigns them to the activities they selected. You can also easily update the roster for any activity with just a few mouse clicks.
When editing the activity, you can choose to send an email from there and you have several options regarding who to include.
You can create jobs and specific shifts for you activities. You can even add items you need people to bring. Volunteers can log in from home and sign up for shifts or commit to bring a requested item.
HelpCounter will even email them reminders of their shifts ahead of time.