There is one hugely annoying problem with Gmail and many people are frustrated with it. It's the spam folder falsely identifying legitimate email as spam. This happens to me quite regularly and I've lost several important emails this way. Many people including myself use Gmail with an email client like Outlook, or Thunderbird over POP3. Everything works fine until someone calls you up and asks why you haven't responded to their email. It turns out that their email was delivered directly into the spam folder. When this happens there is no way for you to know unless you use the browser interface to check. On top of this, the "spam" gets automatically deleted after 30 days, so you have to check at least once a month and wade through potentially hundreds of emails if you don't want to miss anything.
I've done some research and discovered a few things. I looked into creating a filter to move spam to the Inbox. Unfortunately Google allows you to move it into any folder (more accurately, tag it with any label) except the Inbox. That seems strange.
I also tried tagging it with a label under the premise of something with a label shouldn't be considered spam. That doesn't work either. I also looked into turning off the spam filter. Conveniently enough, Google doesn't offer this function, which would be quite trivial to implement I might add.
When creating a filter, you also have the option of forwarding messages. For some strange reason, trying to forward anything in the spam folder does nothing. Looking around on the Internet for some independently created solution turned up nothing as well. So, for whatever reason, I've come to the conclusion that Google doesn't want their spam shared with anyone! That's why it's so hard to get at it. Maybe they want to have an edge in the spam filtering business? Well, if so, they need to do a better job. A lot of people believe that Google has a good spam filter. That's because they hardly ever see spam end up in their Inbox. However, I believe that people don't realize the real problem is that legitimate emails are ending up being marked as junk.
What I really want to do is collect all the spam in Outlook and have my own spam software which actually works, filter the email. Unfortunately, I don't think it's possible. The only solution is to login using the web interface and manually sift through all the junk mail. This is too time consuming and not a good solution. But, I think it's all we can do for now. If you are looking for a solution to this spam problem with Gmail, I hope this save you some time. You don't have to go through the steps I went through. The definitely don't work.