I honestly have no idea how I lived before I used Gmail's filters and labels. I feel without them your inbox is extremely unorganized and messy. I have filters for all kinds of things; differentiating emails from work and school , trashing automated time card notifications and University quarantined emails, and labeling newsletter subscriptions. However, one of the "set-and-forget" filters that I often overlook is my "Spam mark as Read" filter. My friend Dave happened to show me this tip, and I give him the credit, however I cannot for the life of me find the link that he showed me.
What this filter does is, rather than being notified by a Spam counter, the email is instantly "marked as read." This essentially means that you will no longer have the Spam count sitting in the left column mocking you every time you log into Gmail. To top it off, Gmail automatically deletes all Spam that is over 30 days old. This is nice because if you are super paranoid about Gmail incorrectly marking Spam, you'll still have 30 days to catch it before it's gone. Later on I will show how you can avoid such situations.
The filter is incredibly easy to set up, here's how:
1.) Up at the top of you're Gmail page, click on "Create a filter."
2.) In the "Has the words" box, enter "in:spam" (minus the quotation marks)
3.) Click "Next Step." You'll get a Warning saying that "in: will never match incoming mail" however, Spam is an example where this is wrong, because Gmail automatically places Spam mail into the Spam Folder. So you can click "OK" and ignore this warning.
4.) Last, simply click on "Mark as read," and if you'd like, apply this filter to all current conversations below by checking the appropriate box.
Other Notes: After a few weeks of running this filter, I noticed, just a few emails that were not actually spam, but were being marked as spam. Since this filter disables the notification of new spam, you'll have to make sure to check back periodically at first to make sure it is not throwing away stuff that is actually intended for you!
Soon after realizing this, I decided to modify the Filter (go to "Create a filter" and then click on "Show current filters") by adding (again without the quotation marks) "my first name, my last name, my school, and guitar hero" (since google seemed to be marking my RedOctane newsletters as spam) this tells the filter NOT to mark emails containing these words as read, and instead will show you the Spam Count. You can then view the supposed Spam and modify the filter accordingly.
Good luck! Tell me if you have any ideas for filters.
Edit: I found the original blog post that I got the information found here.