I keep reading reciprocal linking is worthless (from a Google ranking perspective) from so called SEO experts, but they never supply proof. It’s all supposition, not actual scientifically collated evidence.
I don’t do too many reciprocal links (not in the classic sense anyway), but many of my own websites link back and forth (a LOT) and they do great in Google because of it, some of my sites ONLY have reciprocal links from my other sites and my sites see over 20,000 unique visitors a day. If reciprocal linking was some how downgraded I’d see many of my websites traffic decreasing because my sites link back and forth so much (all the links would be worthless). Yet my traffic keeps increasing on sites not using affiliate content (thin affiliate sites die traffic wise no matter how many links).
What I think is happening here is a problem with classic reciprocal linking giving the impression reciprocal linking is worthless.
Reciprocal Linking Example
Other than PR the pages below are all equal with 10 links in total from each page.
Page A (PR4) links to Page B (PR4) which links back: overall gain/loss in PR to either site negligible. Small increase to ranking due to having a link using relevant anchor text (assuming the anchor text is good).
Page A (PR5) links to Page B (PR4) which links back: Page B gains PR/link benefit Page A’s site looses PR/link benefit. Both gain due to anchor text, but Page B also gains a little PR (not much though because it links back) which helps at the expense of Page A.
Page A (PR7) links to Page B (PR2) which links back: Page B gains PR/link benefit Page A’s site looses PR/link benefit. Both gain due to anchor text, but Page B gains a massive amount of PR/link benefit which helps a LOT. Next update Page B might be PR6, however the site Page A is on just lost the equivalent of a PR6 page worth of PR which could decrease current SERPs because that’s like the site just lost a PR6 page!!
How often can you setup a PR7 reciprocal link to a lower PR page of yours though? Not very often, so most reciprocal links result in little benefit passed. This doesn’t mean Google downgrades reciprocal links, it’s the nature of reciprocal linking. You can find sites that have hundreds of reciprocal links with just a PR4 home page because they give away as much link benefit as they gain.
Note: With any linking arrangements that result in an increase in PR it’s going to take over 9 months for the transferred PR to show full benefit (see Google Sandbox Effect) and so you have to keep those links for a year to see significant benefit. By that time the webmaster won’t associate any gains to what they did a year ago..
Compare this to Non Reciprocal Links
Page A (PR4) links to Page B (PR4) which doesn’t link back: Page B gains PR/link benefit Page A’s site looses PR. If Page B gets a fair number of these one way links it’s PR will increase a lot faster than a similar number of reciprocal links.
Page A (PR7) links to Page B (PR4) which doesn’t link back: Page B gains a lot of PR/link benefit Page A’s site looses a lot of PR. Page B only needs one link like this to go to PR5 and probably PR6 next update. Like reciprocal links it won’t help until the links have aged at least 9 months to a year. Because it’s not reciprocal all that gained PR will go to other pages on the site and not be partially sent back to Page A.
In conclusion reciprocal links are not ignored by Google, but by the same token don’t expect miracles from a handful of reciprocal links, chances are you are sending away as much benefit as you gain.