Unless you know that the sponsor is a responsible entity, don't click on anything in a spam. Any reply verifies that a live body is on the other end of the connection. Even opening the email could verify "life" because there will be a web beacon in the email body. I use a text based email client that will not view any remote content -- effectively neutering the beacons. If there is any sign of "life", your email is worth some money to those who sell "verified" lists of email addresses.
Lately, I've been using a filter that recognizes key words, such as "Viagra," "Oprah," and "DR OZ". In addition to routing them to a spam folder, the filter replies to the sender as a "505". It is very clear to the sender that the receiving mail server has not delivered the message and there is no point targeting this address in the future. This is not a perfect scheme, (if no one responds to the "505"), but I have noticed that my level of spam seems to be capped, rather than expanding. From time to time I must add to the keyword list. For example, "Trump" has recently become an item.
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I think that there should be some explicit charges associated with sending email. Currently, the cost is so close to "free" that it is a no brainer -- send millions, maybe a few will stick. These charges could be very low, perhaps a fraction of a cent each, but since this would show up on a spreadsheet somewhere, it will make the senders be more selective.
Some of the spam is an attempt to inject Trojans that can then be strapped into networks of spam bots that are even closer to "free". Spam bot networks are rented by the hour. Since the bot networks contain tens and hundreds of thousand active members, this is a very low cost way to reach tens and hundreds of million "customers". Again, if there was a charge per email, these Trojans would show up on a spreadsheet somewhere and someone would become interested in shutting down the Trojan.
These charges would also leave tracks that could be used as a tool for tracking criminal and state sponsored gangs.
