Browser RTS City Building Games.

I love that guy he is awesome and deserves to run those games

 

The Grid is really a lot nicer to the gamer. Yeah, you can still get looted if you don't log in at least here and there, but they've chopped away all the unneeded parts of an RTS game and just left the fun stuff.

celtruler.com/games/thegrid/

It's an elaborate system made up of row upon seemingly endless row of perfectly chiseled squares, each ruled by either a fool or master strategian.

Once you enlist into this new world, you will be transported into The Grid in the form of a single entity known only as: a square. You will rule this square - or see it ruled by another.

Upon logging in, you will notice many other squares, fighting for survival, or to spawn themselves like amoeba unto the far corners of The Grid. If your spectacles are not too foggy from the freezing air in this wondrous utopia, you will notice a...

 

Travian is pretty good and you can achieve a success there if you catch the meaning of the game in the beginning of it.
Unfortunately i lost it... but i'm sure it was because i'd not read the preview before... There's a really good list of browser RTS games here:
List of Free Browser Based MMO Strategy Games