Much of my application development has been "data structure centric". Future projects might be in the same vein so while tinkering with Android coding, I'm looking into 2 major database products with hooks into Android (among others devices, languages, and platforms, of course).
Amazon's AWS has been a major web services provider for awhile. Their data storage product is Amazon S3 but the interesting part is the AWS SDK for Android which provides S3 storage, database creation and messaging. In fact, Amazon might have made it TOO easy to deploy mobile enterprise ("cloud") apps has this PCWorld article suggests! Once I've secured a moderate amount of Android development knowledge, I'm definitely going to open an AWS account and play around with this API (the AWS Free Usage Tier is free for a year).
Salesforce has moved into the database-as-a-service market with database.com, which as this InfoWorld article states aims to be the "back end for the entire Internet". While other companies are playing catch up, Salesforce appears heavily leveraged into the cloud computing and ASP worlds so they might be well positioned to be a database of choice for mobile developers. Unfortunately, database.com is not really live yet (their FAQ page states the full developer preview is coming out in 2011) so I guess this is the end for now.