Used to be that Google appreciated all kinds of backlinks. Then it got wise to the fact that sites were trading reciprocal links.  And then de-emphasized reciprocal links. Not to say they don’t have any value. But they don’t carry the weight they used to.
So all those directories that require that you have a reciprocal [...]

Off-page SEO basically consists of building links back to your site from other sites.  Google used to like reciprocal links.  (You link to my site, and I link back to yours).  But once the black-hat guys got ahold of this idea, they abused it by building reciprocal link farms with thousands of [...]