subscription block in Drupal 6

I want to add a subscription block to my Drupal site. I found these two module: subscription and simple-subscription. I installed subscription (the first one) and pu开发者_开发知识库t its related block in blocks section to right sidebar region but no block is shown.

Is this module reliable and where can i find a documentation for this module?

My guess would be permission problems.

If you are not logged in as user 1 and don't change default permissions, it probably won't show up.

In answer to your second question, one thing to determine if a module is reliable is to see how many other sites use it and how actively it is being worked on. If you see quite a few sites using the module and recent responses in the issues queue, then there is a good chance that it is a quality module or at the very least, being developed into a quality module.

I haven't used subscriptions, but it looks like it is maintained by quality developers and is used in many places. Here is some documentation http://drupal.org/node/344030

You have to configure display settings rightly in admin/settings/subscriptions