Connected Excel means different things to different people.
Most vendors when quizzed whether they connect with Excel would nod their heads vigorously in the affirmative. Sure, they connect with Excel. Have done it for years. Piece of cake. Easy-peasy.
But they could be meaning any of these things:
Type #1 Creating reports in Excel format: Most vendors provide an option in thier reporting application to dump the report in Excel. Once those reports are created, they are spat out on the users file system. Thats it. Done. The Excel file, then, is the usual frozen-in-time Excel file, disconnected with any application, incapable of being refreshed with fresh data.
A variant of this is when the reports are mailed out using some e-mail server to users mailboxes at specified time intervals. The
Type #2 Taking in Excel files as input: Most vendors also provide options for importing data from Excel files. Provided the excel file is in the format specified by them. Provided it lies in a specific directory. Provided it contains no other data. Not your everyday use Excel files, but files specifically created for data input purposes. You could have as well created a flat file.
Type #3 Talking to only "their own" Excel files: Some BI vendors give birth to Excel spreadsheets from their applications, with their VB code in it. This VB code acts like an umblical cord between these Born-to-BI spreadsheets and the mother BI applications. In these spreadsheets, you can refresh data from the mother app, sometimes even upload data to the mother - but these spreadsheets cannot be tampered with. They are special - and you need to take care to let them be pristine. You cannot play with them, cannot put other data into them, nothing.
Type #4 Providing web service interfaces for Excel: For Excel 2003+, vendors claim that they have web services interfaces that can be called using the web query feature of Excel. And vendors actually expect end-users, the average Joe, to make sense out of XML LOL!
There were no credible options to connect Excel with enterprise applications. Not after Extensio came in though!
There are some voices heard about Excel connectivity in SAP's and Microsoft's Duet (formerly Mendocino) , but as far as I could see in the current release, all they do at this time is provide the Type #1 type of connectivity - ie create Excel files - and with its e-mail variant. With the hype that is created and the promises I see in the Duet Colleteral, that was a bit of a let down, but I am hopeful. Surely, biggies such as SAP and Microsoft have more for this 400M strong user application!