I've recently come across several similar posts that have the "feel" of spam, but which are sufficiently outside the Stack Exchange criteria for using the spam flag. What is the preferred way to call (moderator?) attention to the posts? Downvoting? Use the spam flag anyway? Something else?
If you want ♦ moderator attention, there's a special flag for that. In fact, when it's not obviously spam, it's the preferred cause of action; there's no way to add additional information to a spam flag and the ♦ moderators might not see why it's spam without that information.
Downvoting is optional but doesn't get any further attention to the post. You might leave a comment, e.g. linking to this Help Center article in cases where the answer is on-topic but just doesn't meet our self-promotion criteria. Many new users are not familiar with the rules; many other Internet sites don't have such strict rules as we do. In those cases, I normally don't cast a flag; I hope my comment has the desired effect and that the user will become a good Stack Exchange citizen.