I just had a need to do this, and this thread has been quiet for a long time, so I thought it might be useful to supply a recent data point.
In my application roving salespeople use a copy of an Excel workbook that tracks the progress of a prospect through a loan application. The current stage of the application needs to be automatically saved back to a remote SQL database so that we can run reporting on it.
Rejected methods for updating the database from Excel:
SSIS and OpenRowSet are both methods for allowing SQL Server to pull the data from Excel, and don't work very well when the Excel workbook is sitting in an undefined location on a user's computer, and certainly not when the workbook is currently open in Excel.
ADO is now, if not actually deprecated, nevertheless looking very long in the tooth. Also, I wanted the solution to be robust in the face of the user possibly not being connected to the internet.
I also considered running a web API on the destination server. Macros in the Excel workbook connect to the web API to transfer data. However, it can sometimes be painful to allow a web API to talk to the outside world. Also, the code to make it robust in the face of temporary loss of internet connection is painful.
The adopted solution:
The solution I plan to adopt is low-tech: email. Excel emails the data to an address hosted on an Exchange server. Everyone in the company has Outlook installed, so the emails are sent by programmatically adding them to the Outlook Outbox. Outlook nicely handles the case when the user is offline. At the server end, a custom C# executable, fired up at regular intervals by the Task Scheduler, polls the inbox and processes the emails.