Recently I came across a user on a site who:
- Was affiliated with a product/service (according to their profile).
- Was active on the site (i.e. clearly not a spam bot).
- Edited mention of their product/service into other tag wikis (all of these were rolled back by me or others, these were clearly inappropriate).
- Also created a new tag wiki entry specifically dedicated to their product/service, with links to the site, that sort of read like an advertisement. However, there were actually a fair number of questions with this tag that already existed on said site.
So the "edit" case clearly was spam to me, or at the very least, an unnecessary addition of an unremarkable specific product. But the "new tag wiki" case, the dedicated tag, while it feels like spam, it isn't actually that much different than any other legitimate tag wiki entry (description of something and a link to it if it's a product/service). The only potentially "questionable" part was the author's affiliation.
So my question is: What constitutes spam in a tag wiki? What is allowed, what isn't allowed, what rules must be followed, and when is a rollback/deletion justified?