You read Engadget, so you're probably familiar with Twitter even if you're not a regular user. For most other people -- who apparently aren't joining fast enough to please investors -- it's just something occasionally mentioned on the news or Sportscenter. Those people are the ones who the social network's first TV ad is aimed towards. Predictably, the (baseball-focused, since it premiered a few minutes ago during tonight's World Series game) advertisement is all about the new Moments feature intended to organize and slow the flow of information for new users. I felt more confused than ever about Twitter's purpose after watching the 30-second spot, but maybe the intended audience will have a different reaction -- you can check it out after the break.