Viggle, the second screen app for TV that offers discovery, games and rewards for users, has announced that 1.8 million users have registered for its service. Not bad numbers for the startup which marked its first birthday on Jan 26.

Those who use Viggle – amusingly dubbed Vigglers by the company – have checked in on the service 151 million times. A good sign that an engaging service for second screens can really haul in users.

It looks as though it has been a great year for Viggle. Over the past 12 months, the company says that it has given away more than 1.3 million rewards. Using the app, Vigglers can claim rewards from retailers including Amazon, Best Buy, Sephora and The Gap. Earlier this month the company also started trading points for Viggle branded merchandise.

Alongside the branded rewards, the company has also conducted 28 sweepstakes and given away 41 million Viggle points (these are handed out for watching TV shows and can be redeemed for rewards, experiences or charitable donations), a trip to Hollywood and a 3D HDTV package.

Viggle was launched in early 2012. By March it had claimed over a quarter of a million users and by July it had reached one million users. To count as a monthly active users, a Viggler needs to earn or use one point in that month, beyond registering.

In November last year the company announced that it was acquiring competitive social TV app Get Glue for GetGlue for $25 million in cash and 48.3 million shares of stock.

To celebrate a year of growth, Viggle is running a competition so that its users have the chance to meet the company founder and entertainment mogul, Robert F.X. Sillerman. To get involved, users need to send a video message celebrating the company birthday in the least conventional manner they can think of.

Throughout the year, Viggle has been working with some big names as brands experiment with marketing engagement on second screens. Over 40 brands have been involved including Burger King, CapitalOne, JetBlue, DirectTV,  Mercedes-Benz, Pepsi, Verizon and Unliver.

Image credit: Unlisted Sightings / Flickr