I have colaberator that say they can add a row but can not add a column to a sheet... Can this be done or is this a restriction?
It would depend on their sharing level and plan type. Free users and paid Editors cannot made structural changes to sheets (such as adding/removing columns). If your collaborator is a paid Admin on the sheet, they would be able to add and remove columns. Here is information on the different sharing permission levels: http://help.smartsheet.com/customer/portal/articles/1155182-sharing-permission-levels
To add to Travis's comment, in traditional databse development Rows are Records and you expect the users to enter or edit these. Columns are Fields and generally only the database administrator can change the structure.
Smartsheet is not that ridgid in its design but the principles still apply.
