Google's Supplemental results go Mainstream

If your Google searches looked subtly different this morning, it could be because Google has dropped the 'Supplemental Result' label for those pages it tends to consider as second- or third-class citizens of the web.

But just when SEO practitioners were about to shout for joy about their pages 'coming out of Supplemental' (that dodgy backwater where, depending on who you listen to, Google consigns bad or unimportant pages — or simply can't be bothered to scan), they began to realise that Supplemental Hell hasn't gone away: it's just stopped being advertised in the SERPs.

Distinction between Supplemental and mainstream 'narrowing'

Preliminary Webmaster reaction to the move has tended to be negative. Many web teams feel that the absence of the Supplemental label deprives them of an important site metric, and there's a clamour to have the label either restored or at least made available in Google's Webmaster Console. Other SEOs have welcomed the departure of the label as an irrelevance, given that Google has promised that the distinction between mainstream and Supplemental indexes is steadily narrowing.

Reading between the lines of the Google announcement, it seems fair to conclude that that the mainstream Google crawler cherry-picks what it considers to be the prime web pages, leaving what it deems to be iffy or downright dubious to the Supplemental sweeper. These Supplemental results are then reluctantly thrown up onto the SERPs if Google feels it doesn't have sufficient mainstream results for a given search. Moreover, the Supplemental index tends to be stale or stagnant: it's updated much less often than the mainstream results pool.

Problem is, according to many SEO experts, a lot of the 'deep' (or long-tail) pages for a search get buried in the Supplemental index where, by definition, they are deprioritised for the SERPs. For example, take the BBC website. It has about 1.1 million pages listed in Google and of these, a whopping 90,000 or so are up Supplemental Creek. Other SEO professionals tend to believe that Supplemental results were no more than a temporary external glimpse of an internal Google issue, and one which will rectify itself when Google improves freshness and findability of its Supplemental index — something it's promised to do by the end of this summer.