A data-integration strategy needs to be within the foundation of every cloud computing plan. This integration needs to be innate to the architecture; it can’t be something you’re reminded of at the rollout meeting ;-)
But integration of external data sources with the Office 365 cloud is difficult using out-of-the-box features. Business Connectivity Services are provided, but they require programming and access to the remote enterprise data from outside, e.g. by web services.
3rd party tools could help in this case. The Layer2 Cloud Connector for Microsoft SharePoint and Office 365 takes local line-of-business data to the cloud-based or any other hosted SharePoint. Content hosted in almost any corporate data source, e.g. databases, files, ERP/CRM/ECMS or other legacy platforms and on-premise applications like Exchange, Active Directory or even SharePoint itself is replicated to native SharePoint lists in the cloud via secure web services. All features of native SharePoint lists are completely available for the external data.
For example you can start notifications or workflows in SharePoint when external data is changed in the data source.
While the SharePoint Business Data Catalog (BDC), the SharePoint Business Data Connectivity Services (BCS) or the SQL Server Integration Services (SSIS) out-of-the-box are not made for cloud-based scenarios, the SharePoint Cloud Connector was especially developed to solve the specific challenges of disconnected systems in the cloud without any direct access to corporate business data and very restricted feature customization capabilities.
Just try it out. My personal fav is the SharePoint to SharePoint connection, e.g. for content deployment or aggregation. The Shareware Edition is FREE to use (with limited features). You can download after registration today.