Matt explains that while Google may test a new change each day, these arent released worldwide on a daily basis, instead they will usually be released in batches along with other changes.

While Matt notes they probably made around 350-400 changes in 2009, search engine land suggests this figure may be conservative, pointing to a story where Googles head of search noted they made 550 improvements in the past year.

Either way, the figures show Google still believes a lot of improvements can be made to their algorithms.