They're at it again, this time over the size of their search indexes.

With Google currently claiming around 8 Billion indexed pages according to its homepage, Yahoo! has, rather unusually, announced that its search results are based on an index of over 20 Billion, that is over twice the size.

In the Yahoo Search corporate blog at http://www.ysearchblog.com/ they disclose that the index is comprised of:

• 19.2 billion web documents
• 1.6 billion images
• > 50 million audio and video files

which is a seriously impressive amount of content.  In the UK this wont make much difference where according to the May 'Online Search Report' by Hitwise UK, Google UK still has the clear majority of traffic powering 69% of searches, but it does give them something to worry about.

Note: There is also a hint that we may see some changes in the Yahoo! results as they roll out an index update in the next few weeks.