I am thinking of starting this game (after 11 years of it being out I no..), I always thought this game was open world except for dungeon/raid but I read a post some guy on diff forum saying towns/zones are instanced? He lieing or I miss something?

Go to Youtube and look at videos...

Ty.

Aside from the extra people from other realms like if every1 playing on x realm went to x town would they all be able to see eachother? (also same question for x monster area, aside from dungeons raids) or would there be like multiple of same town/area on realm like in gw (really dont want this)?

you'd see eachother in the same town/area - its a lot better then GW since in GW once you leave the town if u go out solo, you're literally the only one out there unless ur partied.

This post was edited by J_O_H_N on Mar 4 2015 05:52am

Starting out, you can still run around all day without overlapping areas. You will see other people, which is actually cool.
Starting from scratch (level 1) you will be doing the old game content so you'll be running around all over the place doing quests.
Once you get a bit higher in level and go towards the newer content you will be with lots of other people. If you like to be around others, join a high population server!

So anywhere you go except for dungeons/raids/pvp arenas, if there is 10000 people on server and they all go to the same place they can always see everyone else? Like if there is 1000 people in a certain quest area, would there be all 1000 visible to me or would it be split up like generating same map 10 times and put 100 people per map?

Well the only time you'll ever see this is if new content opens with quests and stuff and your realm is big.
When WOD released you would see much higher numbers than that, but since then it has died down and you'll see 10-20 people depending on what you're doing.

Ehhh, phased, not instanced. If it's load screens you're looking to avoid, don't worry, there will be very few stray load screens.

I feel like you were asking a different question than last two asnwered, so here's my 2 cents lol. Say you join server x, only times you won't be able to see someone from same server x is if they are in pvp arenas, raids, or dungeons. They also recently changed it so you may also see people from servers y and z while on your own x server, but only under certain conditions (which I'm not 100% on), but your own server x population won't phase / instance out.

Edit typos

This post was edited by LightClaw on Mar 4 2015 11:21pm