I have been writing to some article submission sites and usually they ask for keywords, if there are more keywords, it has instructed to place commas, so it think there is no problem with that. However, I also have read that instead of commas, the vertical sign is much more appreciated by search engines, so it would be better to use it instead of commas. It looks like this | This symbol can be obtained by holding the control key and pressing the reverse backslash. Its the key just above the enter key on your keypad. |