Yes of course, in fact we hope you do! Contacting new supporters is a great way to expand your supporter base. You can thank your supporters through your charity account once they have made a donation.
You can also download the contact details of your new supporters from the Marketing Report available in the Reports section of the "My Donations" page in your account. Do bear in mind however that only supporters who have opted in to receive communications from you will be included in this report.