Twitter has unveiled new versions of its iPhone and Android apps as part of a bid to spread advertising throughout the popular social network platform.

The new apps bring the first mobile rendition of 'expanded tweets', allowing advertisers to show content previews, images and videos in expanded form within a user's tweet stream.
"This new experience will roll out gradually to web, iPhone and Android users," mobile team product manager, Sung Hu Kim, said.
The app updates also bring support for custom, curated hashtag pages introduced to the social network in early June, allowing companies like NASCAR to collate tweets from a selected group of users on a single page.
Users can also receive push notifications from specified users, forming part of Twitter’s drive for a “consistent user experience".
The updates comes as Twitter tightens rules surrounding third party access to its application programming interface.
The company repeated warnings last month of the potential of being cut off from access to the network for circumventing the rules, particularly for those apps that "mimic or reproduce the mainstream Twitter consumer client experience”.
Twitter deemed professional networking site LinkedIn had fallen foul of the edict in June, and cut its access to the network's API.
The social network also cut off access to filters and “mute” features to hide or silence tweets, in an attempt to ensure its advertisements are seen by everyone.
The crackdown on third party apps has been criticised some developers as Twitter turning into a “walled garden” along the lines of Facebook.