In the month since San Francisco-based social network Hi5 launched its platform for independent applications, users have installed widgetmaker RockYou's applications 2 million times. The most popular third-party application on MySpace only has 100,000 installs. The difference? Hi5 links to its application directory from user profile pages and allows application makers to send notification messages to users. Those simple interface elements allow Hi5 users to see which applications their friends are using, which then prompts them to add them, too — the main factor in their spread. MySpace is still working on those kinds of tools, reports VentureBeat. Facebook built those types of innovations into its platform nearly a year ago.