i dont really care about Valve and Steam since Half Life 2. but after the rumor Steam Zenimax deal now im curious. Whats really steam all about? And why that was important not only in valve but in other companies such as Zenimax, EA and even google? Seem its Valve's most priced possesion.

It's quite possibly the most sucessful PC game download service available and they are essentially like platform holders getting a small percentage of each download. Highly profitable for Valve I'm guessing. It also has a large and loyal community to rival that of X-box Live and PSN and will likely only grow.

Also, having a download service like Steam prevents second-hand game sales.

If I cant get it second hand why not pirate it? Doesnt seem like a good thing to force people to choose between free vs 50$,

WOW I wonder if either big game companies could exploit the service? The  possibilty was endless. Though I wonder why Gabe dont want to share Steam. I only know now that Valve was a private company...

They could, but I'd rather they didn't. Valve have been treating the service and their customers with great respect that I don't see that continuing from some larger organisations. With Valve being so small I think it actually benefits the service they provide. PC gamers especially can be a fickle bunch and a larger corporation sticking their nose in could really ruin the community.

Really? BTW whats the online community on CS on steam? I didnt played online since the steam takeover and the game becomes dgital download than a CD form.

If a game is only available on Steam then it makes piracy that much harder. Also, with Steam, they try to offer a greater package and a community giving better value to a game sale, not to mention the numerous deals they have on practically a weekly basis. Games available at retail as well as Steam are a bit more of a problem, but you have the option to buy them either way. If you're going to pirate it then you were unlikely to buy it in the first place so it's not really something that can be countered. Valve wouldn't get any money either way.

For me, I never sell my games second-hand so its not much of a problem.

Well Steam now has many similarities to Live. You have a friends list kinda like MSN and can set up games and see what everyone else is playing and join in. Also they have numerous groups (I believe VGChartz has a group although I'm not a member as it's by invite only) so it makes it easier to set up games if you're a member of a clan. I haven't play CS for a while... I think the only game I've played on Steam recently  is Left 4 Dead, but I haven't played online for a while. I'm sure other user can give you some better details.

well if it will be like the activision blizzard buyout, zenimax will leave valve alone let em do their thing give em money as a publisher and take care of getting marketing done, all the while they get a stake in the profit
there hasnt been any noticeable differences in quality in terms of bathesda so im not worried i think itll be good for em, valve will have a large name like zenimax behind them and that leaves zenimax to handle everything the normal publisher would

Steam is easy and inexpensive. I've bought three games from it. I paid $8, $5 and $0. I don't have to DL these games to a PC to play them. If I want to play them at home, in the living room, at my friend's or at my parent's, I just get on Steam and play them.