Support UDF(User Defined Function) in Excel Online
Without supporting UDF (User Defined Function) in Excel online, this service is pretty useless for any professional Excel users or any corporate environments where Excel VBA, Macros, Add-Ins are widely used.
And, do not forgot, Google Spreadsheet already has it. A lot of people think UDF+Macro are the main advantages Excel Desktop version really has.
Toan Tran commented
Google Spreadsheet is better with UDF, it's fast and simple
Anyway UDF support is must have feature for all Excel versions!
Ajay Gaikwad commented
Supported UDF(User Defined Function) in Excel Online