During the final day of SMX East, Nick and I sat in a fascinating session where search engineers from Google, Yahoo! and Microsoft all answered questions posed by the audience and filtered by moderator Danny Sullivan. I have, in my 5 years of search conferences, attended numerous sessions like this, but I must say that this was, if not the best one I've attended, very close to it. The questions were excellent and the responses were forthright, honest, direct and never condescending. It was not only refreshing to hear, but remarkably valuable.

Below, I'll share the top 6 takeaways I got from the session:

  1. Using Session IDs
    Generally speaking, it's a bad idea to put session IDs in the URL. The engines mentioned that they have standard de-duping of session IDs in URLs (and we do it with our Linkscape index, so it's hard to imagine the engines could be less advanced), automatically canonicalizing such uses as SESSID, SESSIONID, etc. However, it was not made clear whether links that point to these URLs would be counted as part of the original page. For example, if I have the URL seomoz.org/blog?SESSID=123 and the URL seomoz.org/blog, those might be treated as a single URL for retrieval, but whether the latter would receive the PageRank/mozRank/link popularity score assigned to the former was less clear. To be safe, smart SEOs should, if possible, not use the IDs in the URL and, if they are employed, use 301 redirects to ensure proper flow of link equity.
  2. Affiliate Links
    Shockingly, when asked point blank if affiliate programs that employed juice-passing links (those not using nofollow) were against guidelines or if they would be discounted, the engineers all agreed with the position taken by Sean Suchter of Yahoo!. He said, in no uncertain terms, that if affiliate links came from valuable, relevant, trust-worthy sources - bloggers endorsing a product, affiliates of high quality, etc. - they would be counted in link algorithms. Aaron from Google and Nathan from Microsoft both agreed that good affiliate links would be counted by their engines and that it was not necessary to mark these with a nofollow or other method of blocking link value.
  3. False Positives in Spam
    Although the percentages are low, the engines generally agreed with Aaron (of Google)'s position that it does happen and they do request feedback if/when you think it's hit your site. With Google, you can send feedback through Webmaster Central, with Microsoft, Webmaster Tools and with Yahoo!, the Site Explorer Suggestions forum.
  4. Links Are Still Huge
    When asked if links are the primary signal for search engine rankings, the engineers generally agreed that, yes, it probably is. Aaron noted that links are a far less noisy signal than many others, including some forms of on-page keyword use and clicks in the SERPs. Sean from Yahoo! said that while it may not be the "most important signal" by itself, it's more important than, for example, title tags (which SEOs generally agree are critical to the SEO process). There was no mention that links would be fading away anytime soon - or that any competing signals had yet entered the marketplace as a potential usurper.
  5. Sitemaps Shouldn't Be Ignored
    At the beginning of the session, all three of the panelists talked about the value and importance of Sitemaps. Their advice included:
    • Sean from Yahoo! - Put really important pages in your sitemap, rather than every page on your site. Yahoo! considers sitemaps when figuring out which pages are valuable on a site, and if they believe this to be a trusted signal from a publisher, will use it more (the other engines seemed to agree).
    • Nathan from Microsoft - URL structures in sitemaps are very important. Use the shortest, most authoritative, canonical version of the URL you want in the search engines' index in your sitemap file and they'll use that to help automatically filter duplicates and figure out which version to display.
    • All three engines seemed to suggest, somewhat overtly, that sites often see an increase in search traffic when they use sitemaps. I'm not surprised - after building just a small portion of a search engine with Linkscape, we can certainly feel how and why engines would appreciate and bestow benefits upon those who properly incorporated sitemaps.
  6. PageRank Sculpting Should Be Tested
    The engineers all felt that "PR sculpting" - the practice of using nofollow to flow link juice to and through a site to maximize and control how it was assigned to internal pages - was, generally, something that could potentially provide value, but certainly doesn't belong near the top of the SEO priority list. Instead, they all agreed with Danny Sullivan's position that it was something to test to see if your sites/projects receive value from it, because not everyone will.

Naturally, any time the engines give disclosure of this degree, more questions are bound to crop up. If you have any relating to these, or other issues, leave them in the comments below and I'll do my best to get them in front of the search engine reps at the next opportunity (possibly Pubcon, maybe before).

p.s. Hat tip to the very solid coverage of this session by Virginia Nussey.

p.p.s. One more item of value that I picked up from this session is in our PRO Tips section - A Half Dozen Brilliant Link Acquisition Queries.