Steamgifts Levels (CV): Understanding the maths?

You giveaway games, you get CV added to your account which makes your level rise. Ok.

To be clear - values are based on the US store prices in particular.

This real value is calculated according whether they were bundled once: for ever or for a period following it?

After a game lands on a bundle list, any GAs for it after that date are counted as bundled. Giveaways made before still count as unbundled.

It is also calculated depending on whether this is a public or...what, private, "whitelisted", grouped giveway?

No.

Your level experience is then added depending on the number of users?

You need 5 entries to get CV from a giveaway. Anything above that makes no difference.

This real value is calculated according whether they were bundled once: for ever or for a period following it?

Forever. If a game is considered bundled the CV is 15% of the value of the game from the date it became bundled.

It is also calculated depending on whether this is a public or...what, private, "whitelisted", grouped giveway?

Not a factor. The only thing that will also effect it is if less than 5 people enter, you get 0.

Your level experience is then added depending on the number of users?

No idea what you are asking. The CV level increases as you give away games. Each level is harder to reach than the previous one.

@3 Once a bundled game forever a bundled game - otherwise people would just wait set amount of time for it to get unbubdled to get full Value.
@4 All GAs give the same Value. Only difference is that Private/Group/Whitelist GAs need at least 5 entries to give Value at all, otherwise they will give 0 Value. 5+ Entries Private/Group/Whitelist GA will give you the same Value or 1+ Entries Public GA of the same game. The restriction is here to fight exploitation for Value farming.
@5 See above. You get the same value (experience) no matter number of users joined (if you meet 5 entries criteria)

Oh, and treating SG as investment platform is really a bad idea ;) You will need shitload of time either contributing or attending community to solve puzzles, get into private GAs, get whitelisted over your forum posts/topics for it to pay off. If you're looking for easy investment you'd be better buying these games yourself ;) If you want to give away games - it's good platform for you. If you're looking for trading games - it's good platform for you. If you think that you will give away X$ valued games and in return will win X*n$ Value games you will be dissapointed.

Don't look at my profile, it's really not representive for most of the community ;p

Seems like everything is answered, so I thought I 'd drop by with some links you may not have seen. While you're at it, Please read the FAQ and guidelines. Another nifty tool is the search bar right under the new discussion button that allows you to search for questions already asked such as this one. If you want to have some fun comment formatting is here. Here are some good threads as well.

How do I check if a game was already bundled?