You may have heard over the past month about Google's new search index, Caffeine. While a ton of work and updates went into Caffeine, the main thing of interest to users is that Google's search results will be more up to date. This was a necessary move by Google as the web itself becomes more dynamic, with content from blogs and social sites representing a larger chunk of the relevant web. Until recently, a current blog post might not show up in a Google search for a couple weeks; now, you will likely be able to find it through Google in a matter of days.
What's an index?
We've talked previously about how Google and other search engines work, but we didn't specifically talk about the index. When search engines are ranking websites for search results, they aren't actually ranking the current sites; they're ranking a regularly updated and analyzed copy of that website. All of those copies comprise the index. So Caffeine basically gives Google a fresher copy of the Internet to use when delivering search results.
What does Caffeine mean for searchers?
For the most part, your Google searches are likely to look much like they did before, but are more likely to contain pages that were updated or created recently. There also seems to be an increased focus on providing results on media such as images and videos, but for the time being, text is still king both in terms of content and especially in search. An open question is whether the rapidly refreshing index also indicates an increased focus on fresh content relative to content relevance. While there's no control performed with the old index, Small Business Mavericks have noticed some markedly non-relevant results with the new index.
What does Caffeine mean for SEO?
Caffeine has only been live (other than opt-in options) for about a month, so I think it will take some time to figure out what impact Caffeine is likely to have on SEO. In particular, a large part of SEO is based around what competing sites are doing, so I'd imagine there will be a bit of an equilibration phase as people try to map out the new space. That said, it seems likely that a faster index will increase the importance of creating new (and good) content, and the apparent increased focus on other media types may provide some additional opportunities as well. The main thing that excites me from an SEO standpoint, however, is that a quickly updating index can shorten the evaluation time when trying to optimize your site. This faster feedback should significantly speed up iteration loops during SEO. As such, that change in speed is likely to be the biggest benefit in how Caffeine impacts not only the user experience, but also SEO.