There are many ways to use Twitter, one of which is to get an app installed on your mobile phone. If you use Twitter in this way by viewing its mobile site you will soon see a difference on screen. This is down to the addition of adverts on the mobile version of the site.
Users who typically access Twitter on their computers will already be seeing these adverts. However, if you only ever use the social media site on your mobile phone you will notice that Promoted Tweets will start popping up in your timeline. These are tweets that are essentially adverts, and they come from large companies and brands. However, you will only see these tweets if you happen to follow the companies or brands that are promoting them.
This means that not everyone will notice a difference in their use of the mobile site. It does mean, however, that those who do start seeing the Promoted Tweets might elect to stop following certain brands if they feel the tweets become too regular. Since these tweets have launched on the main site there has been little news on how successful (or otherwise) they have been. Nevertheless, since Twitter is aiming to monetise the site to bring in more profits, it makes sense that they would extend the Promoted Tweets to their mobile site.
The main thing to note is that it will have a small start. Later on, more users could see the Promoted Tweets – and this may not be desirable.