You can share a link to a pattern so that other people can purchase it too. No copyright problem with that.
Also, it's quite permissable to give the pattern name, pattern maker's name, and any other info about the pattern for people who want to search for it themselves (if you don't have a link to the pattern online).
For quilter's who have made up their own quilt without a pattern, putting the words "NO PATTERN" in the post will save having to answer lots of inquiries about the source for the pattern.