I believe these subscriptions are by blog and not tag/topic.
If you create multiple blogs on your portal, then you could trigger a workflow from the form that subscribes them to a particular blog if they've selected it in the form (each blog has it's own subscribtion contact property).
I don't think there's a way to subscribe them to a particular tag/topic in a blog.
I believe these subscriptions are by blog and not tag/topic.
If you create multiple blogs on your portal, then you could trigger a workflow from the form that subscribes them to a particular blog if they've selected it in the form (each blog has it's own subscribtion contact property).
I don't think there's a way to subscribe them to a particular tag/topic in a blog.