Google makes adjustments to its search algorithms every day, but sometime last week, it made one that was bigger than the average tweak, and a lot of webmasters took notice.

The comments about ranking changes poured into the search forums and other channels, but Google didn’t indicate it had launched a major update like it sometimes does. You can browse through over 50 messages from webmasters beginning on February 2 here.

SEO forum watcher Barry Schwartz took note as usual and pulled together some charts showing some significant pattern changes at the turn of the month. He asked Google about it and was told that the activity was not related to Panda or Penguin, and got this vague statement from the search giant:

Thanks for checking in — as usual, we’re continuing to make tweaks, but we don’t have a specific “update” to announce.

A lot of people suggested that the tweak was related to mobile, but that’s still up in the air. On Sunday, SearchMetrics shared some findings, including that e-commerce sites appear to have been affected, and that this may or may not be related to the the mobile changes webmasters have been noticing. Both developments, it said, seem to not be completely rolled out yet. They also noticed that some sites that initially lost rankings got them back.

“This development is mostly concentrated on e-commerce and keywords with measurable CPC,” writes Searchmetrics founder Marcus Tober. “Affected sites are mostly retailers, shops, price comparison etc., but of course not limited to that. We noticed two things: first, a loss of a few positions (affected most “loser keywords”), and secondly a total kick-out from the top 100 (affected a small amount of rankings). The pattern is dominated by losing just a few rankings, which of course is reflected in traffic losses.”

“One interesting observation we made was for search results for brand keywords with typos, like ‘addidas’ or ‘adiddas’,” he says. “Before the recent change, mostly price comparison sites, shops and small ad sites ranked here. Then Google started to treat the keywords equally as brands. “As usual” the brand ranked on position 1 with Wikipedia right behind – which represents the typical search results for a brand. Now the SERPs look brand new.”

Searchmetrics also found that for correct brand searches, some smaller providers saw gains while some bigger ones dropped. Check out Tober’s post for additional analysis, but remember it’s still early on this one to come away with any real tangible takeaways.

In terms of mobile, Google has been largely expected to roll out a new mobile ranking signal.

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