Where do I find info on each realm?

So I found a little info in the forums about each realm such as this:

Q: What are the rates of all of the realms?
A: Lordaeron is x1 across the board. Icecrown, Frostmourne, Outland and Frostwolf are x7 XP and x3 everything else. Blackrock is instant-max-level pvp-only.

and

What are the realm's rates?
[wotlk] Lordaeron: x1
[wotlk] Frostmourne: x7 experience, x3 gold rate, weapon skills, profession and reputation rates
[wotlk] Icecrown: x7 experience, x3 gold rate, weapon skills, profession and reputation rates
[wotlk] Blackrock: Instant 80 (only PvP)
[mop] Frostwolf: x7 experience, x3 gold rate, weapon skills, profession and reputation rates

But is there anything else different? Why is Icecrown so packed compared to Frostmourne which seems to be the same rates?

you can find better info at character selection:
Lordaeron: https://i.imgur.com/TzF4hUR.png
Frostmourne: https://i.imgur.com/uHz68bC.png
Icecrown: https://i.imgur.com/G045kBV.png
Blackrock: https://i.imgur.com/BeVaIWs.png

Btw:
Lordaeron: it is x1 realm with harder pve content (Bosses of Wotlk raids have more hp, more dmg and shorter berserker timer). It was a "progressive realm" but, since it has bene launched on september 2015, it is stacked at ICC-RS since many years
(no gear on Coins-Shop)

Frostmourne: is a "progressive-seasonal" realm. Which means every year it get resetted for a fresh new start. It emulate 3.0 patch and progress to next the patch every 3 months

Icecrown: it is the older realm, since it is the result of the merge of Deathwing+Ragnaros realms. (that is why is the most populated, it is stuck at ICC-RS since always)

Blackrock: it is the old Wotlk-Arena Torunamnet realm . Instant max lvl, only pvp. You can do Duels, BGs, Arenas (you will face enemy from ice/lord as well in bg/arena)

Thank you for the clarification!