Very nice question. You can communicate with your downline members regularly through their individual e-mail id which is very effective, I have observed. Also send them e-cards in a regular interval with your message.
Besides above, you can also use the group CSA, PSA mailer etc which is very awesome and amazing too. This would also lead you to earn 30 Versa Points per weeks and ultimately make you you advance your rank. Is not it very amazing?.
