There’s a problem with the export feature if you created a custom field. Let say you create a custom field called “Address”. Everything is fine if all that the user enters is “5 Kingston Road” but if the user enters “5, Kingston Road” (not the comma after “5”) there will be a problem. This single field will be split into different columns when exported to csv and view in Excel.
Just to be sure this problem is not associated with WordPress 2.9.2, I upgraded to the latest version of wordpress with no success.