Steam Account and Family sharing stuff - A few queries

well with steam family library sharing you can't play the games on same time ( already been tested many times) maybe you could play only in one case if the other account was offline ( in offline mode )
and about the keys there is no way to check 'em

EDIT I was wrong with my understanding is that as long as you are playing different games you can share the library.

I don't know of a way to "verify" a key, but if you are planning to redeem it, enter it into Steam on the account you would want it and if it is not valid it won't work.

I do enter giveaways but I have found this to be a great site to learn about and check out many new games I would not have come across otherwise.

If I was to set up a separate steam account for my Kids, and then share the specific games they play with them from my account, would they be able to play those games while I am playing a different game on my account.

No. If they are playing a shared game, and you start playing on your account, they get kicked off in 5 minutes. If you are playing a game and they want to play, they won't be able to access your library.

Also how do I tell if a key is redeemed as i had a few duplicate keys and I don't know which ones I have redeemed and which ones I haven't

No way, other than maybe messaging Steam support

Yeah, it sucks. When you are playing a game, the people who are playing your shared games are kicked out.
This even applies to F2P games too! I share my library to my sister, and when I start a game of DOTA 2, my sister cannot play my games.

Google gives a rather emphatic confirmation to the comments above: You can only play simultaneously if you're playing in offline mode, regardless of which games are being played.

Ps, Does anyone else come here mainly to check out the games, not neccesarily to enter giveaways but finds it is a good way to find new games that you've never heard of to check out?

I'm perpetually caught up with Steam Queue, so.. no.
But I do like discussing games and getting better ideas of them from the many knowledgeable and stimulating members of SG, so that amounts to something rather similar, I think. :)

(That being said, regardless of whether its to learn of new games, or broaden your understanding of/get new perspective on games you already know, the forums can be a fascinating place for it. Keep an eye out. ^.^ )

As far as your keys, you've three ways to deal with them:

1. Drop them carelessly and let the first ninja that stops by grab them.
2. Have people ask for the keys, add them to Steam, and give the keys to them directly.
3. Use a group of users you trust to treat the matter with the appropriate respect, make a giveaway for them, and ask them to agree-to-cancel if the key ends up being invalid.

(and technically 4. Throw the key in giveaway not to a group you trust, and risk getting a Not Received.)

(If it's just a matter of (I have 2 keys, but I'm not sure which one is used) then don't worry about it. Put up the key you think is most likely to work, and swap it out if it doesn't.)

Cheers all that clears it up a bit