We can have a long debate about the merits of Twitter. It has its advocates as well its opponents.
The reason I like Twitter is because the travel industry is so fragmented that it is a great mechanism to keep up with the zeitgeist.
No other tool, website, conference or trade association is as effective at joining together so many people from all corners of the fragmented travel industry.
When used for a B2B perspective Twitter is not trivial or banal.
I no longer have to wait for email newsletters (that I never read) in order to find out what companies I am tracking are announcing. I can see what my competitors talk about hence what they consider important. I can see what our customers are thinking (last time we had an outage more people tweeted about it than raised a ticket in our helpdesk). This is all important information to me.
Hence Twitter has become a key part of my daily information and opinion supply.
Now I have a new source of information and insight. The Google travel team have joined Twitter! (@GoogleTravel)
For many smaller companies in B2C leisure travel Google are responsible for providing traffic representing 50-75% of bookings (taking into account organic traffic, PPC & traffic from intermediate sites who themselves have sourced their traffic primarily from Google)
To me any percentage over 50% or so indicates significant risk. Google have dropped plenty of hints that Google Travel is coming and when it does the outcome could well be disruptive, intentionally or not.
Quoting Google from their 2009 Q2 earnings call:

I think it is the case on the vertical side that there is a lot of opportunity to get incremental monetization gains where you can further qualify the leads better for the advertisers.
So for example, the finance area and the travel area are areas where there’s a lot of opportunity to do that, so that you end up putting more information in the ad and then incrementally getting more information from the customer so that you can further qualify whether or not the customer in the finance area is interested in a particular type of mortgage, and then you send them to an advertiser with whom they are more likely to consummate a specific transaction that that advertiser is willing to pay for. So there’s a lot of opportunity there
So we know they are considering plans and are probably either in research or in active development right now.
What we don't know is how Google see the travel industry. How do they form their opinions? What travel industry news do they read? Who has their ear?
For example do they care more about destinations - see the new Google destination pages - e.g. Paris (Worth a look if you haven't seen this style of page yet)
Or do they care more about transport? e.g. information on how to get from one place to another (such as their maps provide). See Google Transit
Or perhaps they care more about products? Are Google's plans based on product reviews? E.g. Here are the hotels in Southampton, UK along with aggregated reviews.
Or perhaps they fancy themselves at providing advice on what makes a good tour itinerary. E.g. Here are tours you can take in London, UK [Citytours functionality]
From what they have released so far it is difficult to read too much into where they are going next. They seem to have a wide variety of online travel services but not the same deep product / price based functionality for flights / hotels that Bing travel has.
As I mentioned earlier, I believe you can learn a great deal about what a company considers important from how a company uses Twitter. Lets take a look at the new Google Travel twitter account @GoogleTravel
They currently follow 93 twitter accounts. These 93 are dominated by big travel brands (airlines, hotel chains, cruise companies), mainstream media and US based travel startups.
They have tweeted travel tips from CNN, they read Hotel Marketing (having retweeted several articles featured there). No Tnooz tweets yet (keep up Google, keep up!)
But these are all large companies. They don't seem to follow many smaller travel companies or tour operators.
I remember last year sharing a platform at a travel industry conference with several folk from the UK Google Travel team. One comment I had from them was that a particular idea wouldn't be acceptable to them because it wouldn't support their small travel company advertisers. Hence I know they care about the smaller companies, just they don't follow any on Twitter!
Who should Google be following on Twitter in order to understand the wider travel industry on a global basis?
I suggest they follow all the Tnooz nodes all of whom are active (or at least exist) on Twitter.
Also I think they should follow the Travel Insights 100 group, a forum of 100 leading diverse travel leaders all active in social media. Single click subscription and further info from Uptake Travel Insights 100
Who do you suggest Google Travel follow on Twitter?