He noted questions about Twitter's use of Rails. The popular social networking site has been reported to have encountered issues in using Rails. But Hansson said Twitter still uses it for user-facing features. (Twitter could not be reached for comment on Tuesday.)

Hansson also touched on the issue of backward compatibility in Rails 3, acknowledging there could be some quirks for developers. "I wouldn't say it's a problem. It's a recognized, inevitable consequence of changing anything. There's some things that won't necessarily just move straight over," he said.

For example, to gain cross-site scripting protection planned for Rails 3, developers might have to make some adjustments in views. But he stressed the changes to accommodate compatibility would be worth it.

"We're going to make such that the pain is going to be worth the gain," he said. "Rails 3 is going to be as compatible as possible."

Due later this year, Rails 3 is not going to be a complete rewrite. "It's not going to solve everybody's problems," said Hansson.