WP like subscriptions

[PLAYBOY]

It would be nice to have a button in every topic so the visitors can subscribe to that topic and get an email reminder for each reply.

1.1.13

[Illori]

there is already a notify button/link in each thread that users can use to subscribe to that thread.

[PLAYBOY]

But i need something like that for visitors though. Cause i accept membership only with invitation so my member count is pretty small compared to my visitors.