Even though 37signals dropped milestones from the new version of Basecamp -- Basecamp Classic still has them -- Roadmap can convert events into milestones. There are several reasons you may want to do this:
You can create events in Basecamp (A) or Roadmap. Then mouse-over the event in Roadmap (B) and click the checkbox. The event will look and behave like an event in Basecamp, meanwhile the converted event will look and behave like milestone in Roadmap.
- If you associate to-do lists with a milestone you can use Roadmap's milestone dependency feature to automatically shift or push future dates when upstream to-dos are running late; or
- Unlike to-dos, which can only have one assigned resource, milestones allow multiple resource assignments