Very limited indeed. I can't remember where I found this, but this is what I sent to a lead who was somewhat interested in MAS90 Online:
Full user access to all modules available with Sage ERP MAS 90 Online, including Accounts Payable, Accounts Receivable, Bank Reconciliation, Bill of Materials, Business Insights Dashboard, Business Insights Explorer, Electronic Reporting, General Ledger, Inventory Management, Library Master, Paperless Office (except faxing), Purchase Order, Return Merchandise Authorization, and Sales Order.