The Los Angeles Business Journal brings you a weekly roundup of L.A. launches.

Gem: The Venice startup has begun offering a digital wallet platform designed to help developers more easily build Bitcoin apps by encrypting and storing their digital currency. “Gem creates a solution where increasingly you don’t need your bank anymore, and you’re in control of your funds,” Chief Operating Officer Ken Miller said. Gem officially launched earlier this week at TechCrunch Disrupt in San Francisco. The company raised $2 million in seed funding in June, a round led by First Round Capital and Tekton Ventures.

Ranker Comics: Polling list website Ranker.com has created a subsite dedicated to comic books and its fans. Ranker Comics is debuting in collaboration with comic book legend Stan Lee and his Beverly Hills multimedia entertainment company POW! Entertainment. Ranker, located on the Miracle Mile, said it gets 18 million monthly unique visitors and processes eight million votes across 400,000 lists a month.

Rowl: The event discovery iOS app helps users host hangouts with friends or find local events such as concerts, comedy shows and sports games. Users can also follow celebrity artists and get notifications on upcoming promotions and shows. Rowl is based in Santa Monica.

WP E-Signature: ApproveMe, an Eagle Rock software developer, has launched a document-signing plugin for WordPress sites. The plugin promises its service is secure and legally binding while customizable to cater to different business needs.

Staff reporter Melissah Yang can be reached at [email protected]. Follow her on Twitter @MelissahYang for the latest in L.A. tech news.