Grey Google logo sparks more speculation

The plot thickens, as Google's homepage has swapped yesterday's bouncing balls for a grey, lifeless-looking logo.

Lifeless, that is, until you start typing a search query - at which point, its letters are illuminated one by one in the search giant's trademark primary colours as a giant cursor blinks between the characters.

Google's designers regularly creates doodles to celebrate landmark events or commemorate famous anniversaries. Now, it seems, they're using the same technique to signpost their own site developments.

Rumours online suggested that yesterday's doodle design heralded the launch of a Google site using HTML5. the design was a teaser for an announcement that Google is due to make about either Chrome or HTML 5.

Today's doodle seems more likely to point to a wider launch for the live, in-line search facility first spotted by UK search optimisation consultant Rob Ousbey when it was being trialled last month.

Other pundits have suggested the arrival of some kind of 'semantic search', which uses complex data about the meanings and relationships between search terms to understand the searcher's intentions and provide more relevant results.

Whatever the explanation, all will be revealed at Google's 'Search On' event, which starts today at 5.30pm GMT in the search giant's native San Francisco. We'll be covering the event live, so watch this space!