DON'T LET THE MONTHLY SUBSCRIPTION SCARE YOU AWAY.
This game is by far, the most detail oriented, player controlled space MMO ever created. EVERYTHING is within control of the players.
The game is comprised of 4 well balanced factions, Amarr, Minmatar, Caldari, and Gallente. Each having their own unique and rich storyline that ties into the backstory of Eve.
Unlike every MMO out there, Eve does not "typecast" players into certain classes, fields, races etc. Regardless of whose faction you choose to align with, you can do anything and everything you wish to. "Leveling up" is a thing of the past, skills in Eve train in real time, regardless of whether you are online or not. Skills range from taking just a few minutes (Level 1 Skills), to some taking a few months (Level 5 Skills). Because of this, it is possible for a younger/newer player in Eve to "catch up" to those players who have played for a few years while they are still getting the hang of the game.
Different Professions in Eve include:
You run "missions" against whatever faction is disliked by your faction. This includes running out to remote areas of Space, "Deadspace," and battling NPC pirates, drones, space stations, control towers, etc and gaining ISK ($)(Interstellar Kredits), for completing that mission. You can loot the wrecks for different equipment to be used on your ship(s) or sold on the market. After sufficient time and skill, you can even salvage your wrecks from the ravages of space, and gain additional pieces of a ship that can be used in the creation of items, or sold on the market for additional ISK. There is no "grinding," or rather, there is only as much of it as you want there to be. Whether you play 5 minutes or 5 years, you are still going to skill up, and no amount of NPC killing is going to make it go any faster. Though, you might become very rich from doing so.
Eve is a PVP game at its core. There is no getting around this fact. At some point, in some fashion, you will be challenged by other pilots in the game, or actively seek out to do it yourself. You will need strategy, tactfulness, and a quick mind to stay alive in the heat of PVP combat. Eve is the only MMO where "griefing" (Stealing other players mission essential items, purposely targeting them or killing them with undue cause, etc) is not only allowed, but encouraged, as long as it fits within the game mechanics and does not cause undue harrasment. There is no "safe" place in Eve. Never fly a ship you can't afford to lose.
There are literally hundreds of thousands of asteriods in Eve. They range in size, density, rarity, type and location. When you enter this profession, you will be flying specially designed spaceships to haul Ore, which is the unrefined material recieved from the Asteroid you are mining. The rarer the asteroid, the more valuable the Ore. The beauty of Eve in this fashion, is that although it is wonderful to mine the rarest ores in the deepest parts of space, the most common ores never cease to be in demand, and are used to refine into large quantities of minerals that build every item in Eve. So even novice miners, ones with barely the skills trained to fly a mining barge, can still turn a decent profit by mining large amounts of the common ores, and selling them on the market.
This is more of a sub profession. This is the ability to take unrefined ores and refine them into their basic minerals. This is highly lucrative. Some minerals can only be found in the rarest of ores, which are in turn found in the rarest of asteroids. Most professional miners can either refine themselves, or know someone who can do it for them. The reason this is a sub profession, is because it takes quite a long time to be able to refine every ore in the game, perfectly. Which means, that there is nothing that went to waste in the process of refining. As a general rule of thumb, minerals are worth more than ores, but only if you can refine well enough that you don't lose ISK doing it. Some miners are quite content with just selling the ore as is on the market, No refining required. Combine this profession with mining, and you have yourself a recipe for success.
This is a very broad profession. It encompasses everything to do with the construction, research, and invention required to craft every item in Eve. From the smallest space shuttle, to the largest starbase. Everything in Eve is craftable, with a few minor exceptions. Because Eve's economy is, for the most part, player controlled, everything within Eve is subject to supply and demand. As someone entering into the Industry profession, it would be your job to find out what is in demand in the Eve economy, and construct it with the purpose of making a profit. This profession is all about providing quality work at a quality price, and being at the right location at the right time to sell it. Or if you prefer, constructing all of your own equipment. The possibilities are endless.
Simply put, this is the ability in an ever-changing economy, to buy low and sell high. Really high. This is also more of a sub profession, in that it ties in very closely to every aspect of making money in Eve. The people entering this profession, can manipulate the market economy to achieve a desired outcome. Whether that be commanding a certain level price on a particular item, or driving down prices by selling mass quantities of a certain item (ie flooding), with the purpose of making that item no longer valuable. It is as much about commanding a profit, as it is making sure your competitors don't see a dime of theirs. This profession most closely ties in with industry, as it is much easier to manipulate a market in your region if you are able to craft the items that are in need, yourself.
This is the profession of hauling large amounts of goods through various parts of space. This is an incredibly dull profession, but can make you large sums of ISK very quickly. In this profession, you will be scouting contracts that require a pickup and delivery be met. You will get paid a certain amount of ISK as a reward for successfully transporting and delivering your cargo. You are the FedEx/UPS of Eve. This is how goods that are made get to where they need to be in order to sell. The pricier the contract, the better the reward. Be warned though, you are hauling someone elses goods, and they will likely require you put up collateral in case the shipment is lost. Not only would you be risking your collateral, and your ship, they still get paid. This is a profession that isn't entered into lightly.
Corporations are like "guilds." It is a collection of players who come together to achieve a single purpose. Not only is this entirely necessary in Eve, it is also a lot of fun. Corporation Management is the profession of running a corporation. This is by no means, a standalone profession, but it can become one. As your corporation grows, it will be necessary to coordinate, plan, and prepare for all of your pilots necessities. Protection, ISK Making, Ship Reimbursement, Fleet Ops, etc. You are the CEO of a corporation that you can design yourself. You'll need to appoint people leadership positions, and grant the rights and titles to handle affairs while you are away. Its lucrative when you have a corporation that runs like a well oiled machine.
Pirating is exactly as it sounds. Your main goal in life is to grief other players. This profession falls into a PVP sub profession because undoubtedly you will provoke an attack on yourself. This is highly lucrative profession. You can camp out waiting for unsuspecting haulers to fly by, blow them up, and take their goods. You can scan down and intercept missions that require a certain item to be returned, and ransom it back to the player. Pirating is an endless stream of awesome.