SAN FRANCISCO : Twitter on Wednesday said it would begin tracking which other applications people have installed on their mobile devices in a bid to better target ads and content. ‘We are collecting and occasionally updating the list of apps installed on your mobile device so we can deliver tailored content that you might be interested in,’ Twitter said in a blog post. Only lists of applications are being gathered, with no prying into what is being done with those mini-programs, the San Francisco based company said.