How to educate people
Things the common user can do:
- Posting this meta question is how you educated me. Other people not marking this as a duplicate (even though it seems pretty similar to previous questions) will keep it in the Hot Meta Posts pool for the full three days, thus maximizing exposure. This can't be done too often, though. Most of the time, the next point is enough.
- Leaving a comment like you did that tells other people to flag it as spam is also a good practice. If I regularly saw that kind of comment after a spam post I would get the idea.
Things that would take more than the common user to implement:
- Make this question or a similar blog post a featured topic for a week. From time to time bring this and other important topics back to the sidebar to educate new users. I don't read old meta posts but I do read the things that appear in the sidebar.
- I like the ideas about having a "report spam" link or a "spam" option in the close vote dialog. However, I'm not sure if this happens often enough to warrant the extra UI space it would take. See Can we trial a line in the close vote reasons other with a link to flag as spam?Can we trial a line in the close vote reasons other with a link to flag as spam? for the discussion on this.