If Google's launch of MyMaps killed independent mashups, then their latest move may be a saving race - or a nail in the coffin, depending on how you look at it.
While MyMaps allowed users to personalize and share maps, Google will go one step further on Wednesday: new features will allow the mashing of data from external sites like Zvents and ChicagoCrime.org. Like Facebook, they're bringing mashups into a platform on the site itself, rather than having hundreds of independent sites using the API elsewhere (actually, in addition to).
Adding data to maps is done via Maplets, which are like gadgets placed on maps (Mapplets were previewed at Where 2.0). If you've already built something on the Google API, it's very easily to create a maplet and thus get your app into the gallery. For users, meanwhile, the possibilities are endless: map crime data, real estate listings, events and more without any coding skills.
I expect data-based startups will rush at the opportunity, much like they've embraced the Facebook Platform. For many, it means more exposure, but mashup makers may also have a harder time getting pageviews on their own sites.