Newsletter questions

This is a problem all subscribers to newsletters have... we forget what we have subscribed to, how to discontinue them or change them to be in digest form.
Normally when you get your newsletter, if it is a legitimate site and organization, there will be information at the end that will tell you where you can go on the Web and on their site to change your subscription or to discontinue it.
It is impossible for any one newsletter Web site to tell you what newsletters you are receiving. You'll need to collect them as you receive them and try to organize them that way.