Caydel’s SEO Blog

Here’s the seventh in the series of videos posted by Google’s Matt Cutts to Google Video over the past year. These are important for every web developer to see. Please see Matt’s first!

See the rest of the videos!

Transcription

OK. We’re back. I want to start off with a really interesting question. Dazzling Daonna wrote all the way from Louisiana. She says,

“Matt! I mentioned before that I love to see a define type post, redefine terms that you Googlers use, that we non-Googlers might get confused about. Things like Data Refresh, Orthogonal etc.. You may have defined them in various places. But one cheat-sheet kind of list would be great.”

A very good question!

So, at some point I’ll have to do a blog post about host versus domain and a bunch of stuff like that. But several people have been asking questions about June27th, July 27th. So, let me talk about those a little bit, in the context of a data refresh versus an algorithm update versus an index update.

So, I’ll the use metaphor of the car. Back in 2003, we would crawl the web and index the web about once every month. And when we did that, that was called an index update. Algorithms could change, the data would change, every thing could change all in one shot. So, that was a pretty big deal. Webmaster world would name those as “index updates”. Now that we pretty much crawl and refresh some of our index every single day, it’s ever-flux, always going on sort of process.

The biggest changes that people tend to see are algorithm updates. You don’t see many index updates anymore, because we moved away from this monthly update cycle. The only times you might see them is, if you are computing an index which is incompatible with the old index. So for example, if you change how you do segmentation of CJK, Chinese, Japanese, Korean or something like that, you might have to completely change your index and go to another index in parallel. So the index updates are relatively rare.

Algorithm updates, basically are when you change your algorithm. So, may be that’s changing how you score a particular page, you say to yourself, oh, the page rank matters this much more or this much less and things like that. And those can happen pretty much at any time. So we call that asynchronous, because whenever we did an algorithm update and evaluates positively, it improves quality, it improves relevance, we go and push that out.

And then the smallest change is called a data refresh. And that’s essentially like, you are changing the input to the algorithm, changing the data the algorithm works on.

So, an index update, with the car metaphor would be changing a large section of the car, things like, changing the car entirely, where as in algorithm update would be like changing a part in the car. May be changing out the engine for a different engine or some other large part of the car. A data refresh is more like changing the gas in your car. Every one or two weeks or three weeks, if you are driving a hybrid, you will change what actually goes in and how the algorithm operates on that data.

So for the most part, data refreshes are very common thing. We try to be very careful about how we safety check them. Some data refreshes happen all the time. For example we compute pagerank continually and continuously. So there is always a bank of machines refining pagerank based on incoming data. And page rank goes out all the time, anytime there is an update with our new index, which happens pretty much every day.

By contrast, some algorithms are updated every week, every couple of weeks and so those are data refreshes that happen on a slower pace. So the particular algorithm that people are interested in on June 27th and July 27th, those algorithms, well that particular algorithm is actually been live for over a year and half now. So it’s data refreshes that you seeing the are changing the way people’s sites rank.

In general, if your site has been affected, go back, take a fresh look and see, is there anything that might be exceedingly over optimized, or may be a bit hanging out on SEO forums for such a long time that I need to have a regular person come and take a look at the site and see if it looks ok to me. If you’ve tried all the regular stuff and it still looks ok to you, then I would just keep building regularly good content, and try to make the site very useful and if the site is useful, then Google should, you know, fight hard to make sure that rank is where it should be ranking.

That’s about the most advice I can give about June 27th and July 27th data refreshes, because it does go into our secret sauce a little bit, But that hopefully gives you an idea about the scale, the magnitude of different changes. Algorithm changes happen a little more rarely, but data refreshes are always happening and sometimes they happen from day to day and sometimes they happen from week to week and month to month.

Transcription thanks to Peter T. Davis