1] A passive-aggressive form of communication to inform someone that their behavior or appearance is not to someone elses liking, or inline with their way of thinking. (This is usually relayed to friends and co-workers using the 2 finger quote motion.) Suggester is usally Clueless regarding the suggesting topic.
2] The Act of encoraging someone else to do something that you don't have the balls to do yourself.
1a] Hey Bob, If i can make a "Suggestion" regarding your report that you turned in..if you could format it... blah blah blah
1b] If I can make a quick suggestion to you...Your breath smells like shit...you should go brush your teeth.
1c] Dude, if i can make a suggestion about your playlist...you should add some more zepplin, cuz everybody loves zepplin.
2a] Well Girl, my suggestion is you dump his ass, and get yo self a real man.
2b] I'd fuck her if i was you, but that's just my suggestion..you do what you want to do