Twitter crossed 1 million registered applications, built by more than 750,000 developers around the world, according to Twitter Blog.

A year ago there was just 150,000 apps. A new app is registered every 1.5 seconds, fueling a spike in ecosystem growth in the areas of analytics, curation and publisher tools.

Since December 2010, more than $500 million has been invested in ecosystem companies, and more than a billion dollars has been paid out in acquisitions. This level of investment is indicative of the opportunity for developers and entrepreneurs to build successful businesses as part of the Twitter platform.

Twitter also introduced a new Twitter Developer site, where anyone in the ecosystem can start building with Twitter, connect directly with Twitter team members, exchange ideas with fellow developers, and find all the resources they need to create their own product or business.

Apps help people understand and make the most of Twitter, whether they’re on the web, on mobile, and even watching television. A few examples: Mass Relevance combed through more than 160,000 Tweets to bring the White House’s first Twitter Town Hall to life though real-time content curation and visualization.