Help me with my thesis

I wouldn't consider Steam a brand. It isn't a product; it's a marketplace where you buy products. Sure, you have things like the SteamLink and the Steam Controller, but that's not what the Steam Community is built around; it's the difference between store-brand products (e.g. the "Great Value" brand from Wal-Mart) and the store itself.

EDIT: as for the games you should give away, they should be really expensive, unbundled games so that we can idle them for cards. ☺ (that was a joke; it's so we can get them for +1 and never play them at all).

Okay, that was also a joke. If you want to be really generous, you could look at the community wishlist and give away a game from there, or if you don't have much money to throw around, you could do what a bunch of other users here do and just buy the latest bundle and give that away.

P.S. The poll is missing an option for "bee see dee eee eff gee."

a.
"A brand is a product, service, or concept that is publicly distinguished from other products, services, or concepts so that it can be easily communicated and usually marketed. A brand name is the name of the distinctive product, service, or concept. Branding is the process of creating and disseminating the brand name. Branding can be applied to the entire corporate identity as well as to individual product and service names."
In this sense Steam is a brand even though they don't produce anything.

b. Contact several and see which is willing to reply then work with what you got. Try EA

c. No idea, but there are many "free" options out there.

d. Don't really care. I have no need for a dangling carrot to help.

a. Steam a brand or not?
I think Valve is the Brand and Steam is the product.

b. Which brand community should I test?
I would go with Valve for the platform created since they stopped publishing games a while ago.
One publisher that seems to be easy to contact might be Paradox Interactive. Here is the Forum. https://forum.paradoxplaza.com/forum/index.php

c. Which survey tools do you recommend?
I worked with Google and Survey Monkey, both are good.

d. What games should I giveaway?
Don`t worry, just happy to help. (I hope I did)

Good Luck

A. Steam is a product from Valve, I guess.
B. I suggest doing various big name brands such as Square Enix, Capcom, and so on. It's probably more specific than Steam Community.
C. Google Form is fine, I don't know if Survey Monkey offers more customization than Google's survey platform, but you could give that a try as well. Sorry, not an expert in that sense. Made my surveys like in the good ol' days (pen & paper)
D. Like devonrv said, if you're feeling generous you could try taking a look at the community wishlist for ideas. Otherwise, it's fine, it's not completely necessary.

Good luck on your thesis!

A. Steam itself seems to be a product, but it's also clearly used as a brand, examples being the Steam Controller, Steam Link and even sub-systems within Steam like Steam Workshop or even Steam Store. I'd say Steam is the main product under the Steam brand.

D.I'd probably just base it off the audience. The Community Wishlist might be a good indicator of what people want on this site. If it's a survey you can ask that question at the end. Or if you end up using a specific publisher, you can base the games off that.

Steam as such is a product. Valve is the company that made it. Just like others are already pointing out.
What do you mean by community ? The people ? The users and clientele of said company ? I think valve (And steam perticularly) would be quit extensive for a reaserch if I understand you correctly (some of your wording seems to be over-complicated :D no offence) . Feedback system, artworks, discussions, groups, greenlight project (and whatever takes its place) , marketing possibilities on Steam.

I mostly have used google forms.

For GA - just a tip - if your looking to make a train or similar, maybe try to include different types of games. That would, in my opinion, get the most attention and feedback from people :)

Good luck :)