Link Text Box contents to cell contents
Text box feature
By Neale Blackwood
Text boxes are useful because you can easily place them anywhere on your spreadsheet. You can link the contents of a text box to a cell. First draw a text box on your sheet. Then when the text box is selected click in the Formula bar and type = then click on the cell to link to. You can link to a cell in other sheets.
Changing the cell contents will change the text box contents. This is useful to put dynamic messages around your spreadsheet. You can use a formula in the cell to create a dynamic text message which will then appear in the text box.