The link to search tips shows up only AFTER you do a search. Plus it's easily missed because when one does a search, one's eyes automatically go to the search result area. The right column by habit is ignored too because it usually has irrelevant data: ads, tag clouds, stats ..etc.
Anything that's used heavily on a site should be put in the FAQ page and that includes search. I have to do a dummy search to get the link to the search tips link. I suppose I can bookmark it.
BTW, why does search on 'user' does not bring up the link?