Perform Calculations (Sum, Count, If, etc.) Based on Cell Color
Allow users to create formulas and that perform specified operations with data/values from only cells with a chosen background color, from a range of cells.
For example, in a range of 10 cells (A1:A10), only 3 cells have been colored yellow (either by the user or by a specified condition). A user can create a formula, such as =SUM or =COUNT or =AVERAGE, that will only use the cells colored yellow to determine the result. All other cells in the range, regardless of background color, will be excluded from the formula's result.
Alternatively, the same functionality can be achieved based on font color, such as values colored red.
Ideally, both methods (cell background or font color) should be implemented since the use of color is a very important and natural way users identify special or standout data. Even on paper we use highlighters of various colors, or red-ink pens to identify data or values of special importance. The most powerful and useful spreadsheet software available should also have this capability, without requiring users to develop complex VBA scripts and code.