The fun of dota is within the heroes and the fast paced action of it, less then the long tearm strategy and planning that are involed in many other aos's, while still having elements of strategy and teamplay it is more a game of countering and timing.
Dota is balenced is not direct, but simply is balences through imbalence, certain heroes own other heroes and certain heroes do not, it is as simple as that.
In public games the gameplay is chaotic and most of the time the teams will fight amongest each other, concerning kill steals and noobies. Ok, now you might be asking your self "how is someone a noob at dota?" it is quite simple, and it comes down to three key factors.
1)Know your opponent: One of the biggest aspects of dota that seperates so called "leet" players and "omgwtfnoobs". Dota is comprised of over 50 heroes and each has there own strengths, weaknesses and extremely powerful abilites, to fight aginest the hero in your lane you must know what abilites they posses and plan ahead so that you can avoid or prevent them from using them aginest you.
2)Item Builds: One of the key points of dota are item builds, the correct items on a hero can make them goldy while the wrong ones can screw him to shreads. Knowing which items work well with your hero and which ones are most effective aginst your opponets heroes is key to dominating the game.
3)Matchups: While it is rare to see the players waiting or discussing which heroes they will pick to fight the opposing team it is still a very importent aspect to the game, if the opposing team has a large number of casters it would be best to pick an anti caster such as the anti-mage or scilencer while if they are made of many assasin heroes it would be best to pick a tank hero like pudge or sven. It is also key to choose your enemy, if you are up aginst your weakness in a lane it is best to change to somewhere where you will not be at a disadvantage.
As a closing note, people do not like people to dl DoTa off of battlenet because it takes awhile and many dota players would rather kick a dler and get another player in a few seconds then wati for him, you can download the newest version of dota from there website.
http://www.dota-allstars.com/
I hope that was insightful into the "deep" and "tactical" world of dota. Bnets "finest" (lol) map.