Lol those games added long time ago and you just post them again, so I assume if someone doesn't have something from indiegala.com/showcase then it's easier to go there and check, rather then wait when someone randomly picks some oldies from it and "discover" them again.
Can you point to me where was posted before?
At least the two "Chichester" games have indeed been posted before here (or in the "Massive Giveaways" thread), but who cares? In my opinion, your list is a useful summary, it's in the correct thread and as long as you (or someone else) doesn't post it every few days, I see no problem with it.
Besides, I think some people in here don't realise that this thread isn't just made for those who read it daily, but also for "random" or new visitors. So when a game has already been free for weeks or even months it certainly cannot hurt to re-post it once in a while because there will always be readers that don't already know about them.