A US website-creation firm called Moonfruit has been getting plenty of publicity this week, thanks to a crafty marketing campaign on Twitter.

They're getting people to put the hashtag #moonfruit in their tweets, and every day for ten days, Moonfruit will choose someone at random to win a MacBook Pro.

As a result, #moonfruit has been the top 'trending topic' on Twitter all this week, beating #michaeljackson, #iranelection and (today) #Murray and #Wimbledon.

So can you as a mobile games developer or publisher learn anything from this? Or, to put it more bluntly, should you be dangling a free iPhone 3GS in front of anyone who tweets a hashtag with your game's name in it?

Well, it's a thought, although there will surely be a limited shelf-life for this kind of promotion, as more brands dive in and Twitterers realise that they probably won't win that tempting prize for becoming a cog in someone's viral marketing campaign.

But if the Moonfruit campaign gets mobile games firms talking about hashtags and Twitter buzz, it will be a good thing. There are some more organic, less overtly spammy ways to take advantage.

Look at what ngmoco has been doing with the Twitter bragging feature in several of its games. Players post their high scores to Twitter from within the games, challenging their friends to beat it.

But crucially, there's a hashtag in every tweet: you can see the results by running searches on games like WordFu, Star Defense and Topple 2.

It's a simple thing, and thus far, these games haven't troubled the upper reaches of the trending topics table on Twitter. But when a mobile or iPhone game does go truly viral - which it will, soon - this will change.

And hashtags are becoming quite an important way to learn about hot topics, products and services on Twitter - helped by the fact that they're served up as links whenever they appear on your Twitter feed.

Anyway, the real message behind all this isn't that hashtags are the future for all marketing - they aren't - or even that Twitter is where you should be spending all your marketing dollars - it isn't.

However, it does hammer home the idea that in the App Store era, mobile games marketing is about keeping track of new trends in social media, and their possible relevance for the campaigns that you're running.

Harder work than in the days when mobile games marketing was just about chumming up to operators, but certainly more fulfilling.

Twitter and other social media sites don't - no matter what the hype says - guarantee an amazing marketing campaign. They're just tools with which canny marketeers can do innovative and exciting stuff.