When Twitter first started you could get your updates for free on your mobile phone through SMS. This is great, until you get more than ten friends and it starts to get annoying. What was good was that you could get DMs (direct messages) texted or just choose which followers you wanted to get SMSs from.

In the US the SMS model works a little better for Twitter as some users have to pay for the texts they receive – therefore Twitter SMS is good news for telcos! In the UK its free to receive SMS so Twitter was finding itself coughing up a load of dough for sending SMS’s to users, therefore it promptly turned them off.

Until this week. It’s announced a deal with mobile operator Vodafone to re-start it, with free texts to and from Twitter. It’s likely that Twitter will gradually roll this out to other UK mobile operators over the coming months. A deal with a telco doesn’t change the poor economics for Twitter, so there’s got to be something in it for Vodafone if Twitter aren’t paying for the texts, and there certainly is if you look at the T&Cs on Voda’s website:

By linking your twitter account & number, you’re agreeing to receive adverts related to Vodafone services in Twitter updates. If you want to stop receiving adverts, you will need to switch off the Twitter updates by sending STOP to 86444.

It makes sense for Vodafone – it’s a good way for them to speak to their customers.  However, this is the first time ads have appeared appended to messages – is it a sign of Twitter’s future business model?