Vanilla socialization & social recognition

Socialization between horde and alliance were a lot better because bgs were fights among players from same server only so high ranked ppl knew each other. Also we knew what guild had the server first or second or third boss kill without the need of achievements broadcasted server wide and we knew who had a legendary weapon and they weren't many, they were max 4-5 ppl in the entire server but this depends on servers guild raid progress.  Link

I wouldn't be able to tell whether the socialization between different factions is better or not on Kronos. There's definitely competition about raid server-firsts between factions and there's a big competition about who gets to be warlord (with some vocal folks on the forums). Some Horde PvP players like their Alliance counterparts and duel them in videos, others hate them to the point of collecting screenshots of all the times they /spit on eachother. There are players offering gold to camp or kill some players.

Helping out a warrior get his BWL attunement. Before his friend killed me.

Overall it's mixed. I have seen both Alliance and Horde raids stopping players from entering UBRS, BWL and MC (admittedly in a disorganized fashion, and I guess it was mostly for fun). But I've also seen Alliance players /bow in front of us, and giving us greetings as we entered raids. Now, players do know eachother quite well (Samsara, Myntone, Quasar, Nedstark & Lazeh are known ranked PvP players on both sides) to the point that some battlegrounds are avoided because they are in them. Guilds have far ranged reputation (just like on retail, think Paragon & Method = Synced, Arcanum & Agony). And legendary carriers get recognised easily, especially when sitting/showing off in Orgrimmar (I know of only one, Nerfmeh, who's got Thunderfury).

Alliance wiping a Horde Azuregos raid at 12% hp

Conclusion

Horde & Alliance players know eachother well. They interact frequently, sometimes in a friendly manner, sometimes not. Best ranked PvP players are well known, just as the best guilds and players that have legendaries. Reputation matters and is server-wide.

[See other articles about Vanilla]