Twitter’s advertising system thus far has been relatively simple for brands. They tweet out a message from their account and then log into the ad portal, pick a region and an ad budget and publish it as a promoted tweet.

Now, Twitter says it will let brands choose to send brand new tweets to a specific region, device and platform right out of the gate, without having to blast it out there to a region, then ‘publish’ it as a targeted promoted tweet. The option to promote a tweet to a specific region has been in the ad portal for a while, but this will minimize its exposure to users who would have no reason to click on it or engage with it in the first place.

Now global brands that have different launch dates for several countries can send tailored messages at different times, customized for the users in each country. Mobile app providers who only want to reach customers on one device can do so without also sending the message to desktop users.

The targeting also allows brands to choose whether the ads appear on desktop or mobile, and on specific device platforms like BlackBerry or iOS. This should build goodwill with followers of brands that aren’t bombarded with ads that have no relevance to them.

To this end, Twitter has introduced a new ‘compose tweet’ box to the ad portal, letting brands make up their tweet on the fly, rather than having to choose one that they’ve already pushed out. It’s calling these ‘targeted Tweets’.

Twitter is also continuing to ramp up its small business advertising program, and has begun sending out email invitations for its promoted Tweets and promoted accounts services. Users who signed up for the advertising program back in March, when it was announced, are now getting their emails, signaling a larger rollout. “Over the last few months, we’ve been slowly making it available to more advertisers,” Twitter says. “We see a huge opportunity here and we want to get it right.”

The tracking on Twitter ads is good, with users responding favorably to the idea of having ads on the web and even in their mobile timelines even from accounts that they don’t follow. A recent report from the Wall Street Journal said that Twitter was generating the majority of its revenue from ads on mobile, and some advertisers said that “results were staggering”.