Spam is a hassle. Newsletters are largely spam in my opinion. I generally didn't opt in (as they claim), at least not intentionally. Although some of them have good content, I want to look at it on my schedule, not theirs. Most marketers of newsletters are ethical and put an "unsubscribe" link of some short at the bottom of their email. This is your opportunity to use that one little word to create a rule in Outlook to move those annoying newsletters to a special folder. In my case, I create folders with an underscore at the front so they are all at the top and alphabetized as I want them.
Here's how to do it in Outlook 2010. Other versions are similar. First find Rules and select create a rule.
Below you will see the rule I created, which triggers off the word unsubscribe and moves all this unwanted newsletter to a folder called _newsletter. You do have to monitor this folder, as I've found it's common for workmates and friends to forward you newsletters that say "check this out". So you miss things if you don't look, but at least you'll clean up your main inbox!