A wrote:
These phenomena seem like something we should address before it gets much worse. I guess the most contentious one would be links to one's own sites on one's User and User:Talk pages. I'm not sure how that line should be drawn. A blanket ban would probably drive some editors away, and any policy would probably have a lot of gray area regarding what's acceptable.
I'm sure that a pretty straightforward addition to WP:SPAM would be relatively uncontroversial if brought up there.
-Jeff