And thus the OP requires better definition. The title "hooked up" can imply meeting someone this way, or meeting someone on a website specifically designed for dating, or meeting someone in a very obviously-superficial way (like on a porn site, LOL).
Here's the thing about the Intrawebz: chat rooms, or posting boards, are great ways to meet people because you can interact with them without physicality getting in the way. You will talk to and share things with people whom you have no idea what they look like, and you might get to know and like people without knowing if they're foxes or uglies or whatever. And there are more boundaries than just looks (such as ethnicity, income, or just general shyness and inability to interact with strangers).
As much as we all like to harp on the sexuality, when it comes to a LTR you do need to actually have things in common, like the person's personality, have the ability to talk to them, and all that other Oxygen Network crap.
Just think about this board, even if you just want to talk about male-to-male (no homo): how many of you guys have met in person after getting to know each other, and thought, "Cool dude," and have never reflected on whether or not this is the type of person you would've interacted with in real life unless it was chasing each other with baseball bats at a traffic altercation?
Long story short, if you spend the time to get to know someone online, you can have an actual "real life" stable relationship with them. If you don't spend the time, or are looking for shallow or one-and-done, you'll get just that. It is what you make of it. If you treat it like a singles bar, you'll get that result; if you treat it like a simple way to interact with people (replacing real-world sites like work, gym, whatever) then you'll get more stable long-term results.