Rumours have resurfaced on the web about search giant Google being in the late stages of negotiation to buy micro-blogging platform Twitter.

Existing rumours have been given heightened potency because Google visual design boss Douglas Bowman recently left the search engine and headed almost straight to a creative director role at Twitter.

Now blog site TechCrunch says it has learned of ongoing negotiations between Google and Twitter. What we've yet to be convinced about is exactly why Google would want to acquire - unless, of course, it simply wants to prevent rival web companies from doing so.

Various industry experts believe the inevitable conclusion of Twitter's success is that it must be gobbled up by a larger concern. Social networking site Facebook last year launched an unsuccessful bid to buy out Twitter as it was losing impetus to it.

Twitter takes the idea of the status updates that appear next to each user's profile on Facebook and has turned the concept into a more-frequently-updated means of telling the world - or at least those that 'follow' you - what you're up to at any given moment.

Facebook offered a reported $250 million and was turned down. With figures that high doing the rounds, Google may be one of the few organisations in a position to afford to buy Twitter.

TechDigest says: "Zuckerburg Inc [Facebook founder Mark Zuckerburg] was looking to use overpriced Facebook stock for the majority of the bargain whereas Google is ready to pay in both cold, hard cash and more stable, publicly-valued shares".

Twitter has been embraced by many high profile people, including Barack Obama, Stephen Fry, John Cleese and Jonathan Ross (Wossy to his followers).

The free service allows Twitter users to update interested parties about their comings and goings as they happen. It's been adopted for everything from updates on comments in Prime Minister's Question Time to breaking news stories and live blogging events.

Famously, it was a Twitter user who first alerted the world to the Hudson River plane crash in New York and posted the first pictures of the aircraft ditching into the sea.

This week, Twitter integrated search into its pages, so bloggers could more easily find topics and online sources about which to tweet. Twitter had reportedly been losing out to its own add-ons such as TweetDeck, which enable users to monitor tweets about specific subjects. Twitter has now made its own 'trending topics' function slightly more prominent in a bid to maintain the currency of the site.

Twitter was heavily used by the media this week to report on the G20 Summit in London, with minute-by-minute updates from all the major online, print and TV news services, as well as various on-the-spot citizen reporters.

For all its appeal, it's not immediately clear whether Google really does intend to buy Twitter and the current web consensus seems to be the microblog would be hard to monetise. We'll wait for a tweet from Google or Twitter itself.