It's not about being free or not. You shouldn't operate with loss only to drive customers away from competition. That being said, I don't believe these laws should apply to online services. It's entirely different market. I was mentioning it because the example with Starbucks couldn't happen, thus it was a bad example.
Anti-dumping laws make sense when you're talking about hard goods with a concrete marginal cost of goods sold (like coffee.) Theydon't make much sense for web sites and software.