There's a rumour doing the rounds that Google is looking to buy Twitter.

Naturally, the story - first reported in TechCrunch - has got the blogosphere all, well, a-twitter with excitement. First of all, it's been ages since we've had a good, old-fashioned "Google-set-to-buy..." story and second, it concerns Twitter, the current media darling and geek fave. And when you consider that Twitter only last week turned down a half a billion dollar bid from Facebook, it also has the advantage of being about big numbers, which naturally gets financial commentators exicted. The thinking is, Techcrunch, postulates, that Google will be able to tap into the rich search functionality of Twitter, keeping tabs on what was being talked about in the here-and-now and monetising that search.

But there are certain aspects of the deal that don't ring true. Fiirst of all, Google already has (or rather, had) a Twitter on its book. In June 2007, it acquired Jaiku, a Finnish company that offered a similar service to Twitter. It didn't stay within Google for very long; in January this year, the company announced that it was ceasing development on Jaiku and releasing the code as an open-source project under an Apache licence. When it bought Jaikum, Google could have acquired Twitter - it would have been considerably cheaper than it is now. In fact, it could be argued that by slowing down the growth of Jaiku it removed Twitter's main competitor, making Twitter more desirable.

So, who knows why Google would be interested it Twitter. Maybe the grand plan is to buy Twitter to migrate it to run on the Jaiku/Google App Engine. This of course would be open platform, encouraging anyone who wanted to offer a similar service to use that platform, and Google benefits by, of course, monetising that search. This would certainly be in accord with the Google strategy of using open-source as much as possible but still looking to be a dominant player in any space.

We can speculate as much as possible. No-one from Google or Twitter is commenting on the projected tie-up, so all specualtion is just that: speculation. And it's interesting to note that TechCrunch has now updated its own story to say that its (unnamed) sources are now claiming that Google and Twitter are only in early stages of talking and are also planning on  working together to develop a real-time search engine.

This one is going to run for some time, so be prepared for more speculation and gossip.

And don't forget one other compelling reason why Google might buy Twitter; simply because it can.