Is spam a form of privacy or security risk?

Answer 1

Not most of it. Spam is generally mail that is unwanted or not useful.

However, a significant amount of spam is encoded in HTML that contains links to images on web sites owned by the spammers. The links also contain unique identifiers that allow the spammers to know the e-mail address to which the spam was sent so that, if your mail reader automatically loads the images, the spammers will know that you received and opened the e-mail--thus verifying your address as an active spam target. Many people consider that a violation of their privacy and some mail readers have features to turn off automatic image loading.

Most spam does not represent a direct security risk. However, some spam contains links to web sites that will attempt to download malware to your machine if you click on them. That is more of a Trojan horse/browser problem than simply a spam problem.

Similarly, some spam attempts to trick people into divulging account names and passwords by directing you to a fake web site which simulates a legitimate site. This is generally called "phishing". Once again, it is not the spam itself, but the web site that it links to that is a threat.

In such cases, the spam could be considered an indirectsecurity risk.