From the beginning Gmail has had a very good spam filter. Now Google added a nice new feature explaining why a mail lands in the Spam filter.

So starting today, we’ll be showing a brief explanation at the top of each of your spam messages. Simply look at any message in your spam folder and now you can find out why it was put there and learn about any potentially harmful content within the message.

But does anyone except me still look into the Spam filter to check the messages that the mail client thinks are spam but aren't?

According to the Email Admin the amount of spam sent is getting less. Personally, I haven't noticed this, but I only get a few each day. However, there are some threats to email security remaining.