Marketing Beta versions is a creative, if somewhat risky, tactic in hyper-competitive, hyper-accelerated, impatient online markets where the notion that things are kind of dynamic and changeable anyway is already pretty well understood.
It’s less polished, less formal, more populist. And those aren’t necessarily bad things. But it also carries the risk of watering down the “promise of performance” that underpins a brand. The emerging philosophy seems to be, “Here, try this out. Maybe you’ll dig it. Tell us what you think. But we’re not making any promises about what it is ultimately going to be—or when.” (StealThunder)
Users are the beta-testers, they improve the product, test its scalability and build the hype. Beta versions are cool because they are unfinished. They look good, but you know you don't see the whole package - there are still things to come. Moreover, you have the privilege to be one of the first persons who can try that product.
That may be the case with developers, adventurers, or teenagers, but I don't think many businesses can afford to use a beta product for corporate work. But maybe that shouldn't be the case.