One of my members has came across some words that are underlined, when he hovers the mouse over the work it shows a link " VIGLINK" should I be concerned?
No this is nothing to worry about it is a setting that you have on in your ACP to remove this you can do the following step
ACP >> General Tab >> Forum >> Configuration >> look for >> Text ads activation for guests(underlined) : mark it as NO then save. and then take a look the words will not be underlined and they will not be linked to anything.
Just to add more to what APE said above this is another method of Ads forumotion uses and is activated by default when you first make your Forumotion forum. You can follow the steps APE gave you above to stop them.