Internet dating is huge, and it's no secret why. It's a simple matter of maximizing resources to attain a goal. Your parents' generation relied upon set-ups and chance encounters to find "the one", but the Internet has expanded your search to include potential suitors from around the globe. Sure, a larger pool increases your odds of success, but it may not translate into finding a mate if you let it go to your head. The trick is in the approach.
Pro: Success is Common
Internet dating works - eHarmony claims to be responsible for over 500 weddings per day, and that is just one of the hundreds of dating sites. Beyond the biggies like eHarmony, Match, Plenty of Fish and OKCupid, there are niche dating sites that cater to just about any social subset you may be a part of - some even cater to married folks. Rather than take your chances with strangers in a bar, you can rest assured that because you were matched based on something, you have at least one thing in common.
Con: Many Facets of Success
The term "success" as applied to dating means different things to different people. Some see marriage as the ultimate goal, while others just want to expand their social circle and go on some fun dates. Be upfront with yourself, and be honest on your profile - don't say you're looking for a soulmate if you have no intention of settling down. Also, be aware that not everyone is as honest as you are, so don't become too emotionally invested until you know the other person's intentions for sure.
Pro: It's Safer
Most Internet dating sites allow for online communication within the system itself, so you don't even have to give out your email address until you feel comfortable with the other person. Many people refrain from sharing a phone number until several emails have been exchanged, and the first date may take place after several weeks or more of conversation. This allows you to establish a certain level of comfort with the other person - unlike "real life" dating, where you exchange phone numbers almost immediately, before you know very much about the person.
Con: Still Not Entirely Safe
No matter how careful you are and no matter how slowly you take things, there is always a risk in meeting someone new. People lie, especially online. In most cases, a person's dating profile is like a resume - embellished, but basically the truth. The picture may be taken from a good angle, the wit and charm may be the product of numerous rough drafts instead of spontaneity, but the essence of the real person comes through. There are, however, a small number of people who flat-out lie. Most lies are relatively harmless - they may be married or have kids, for example, but a psycho stalker would never identify himself as such in his profile. Always meet in public places at first, preferably as part of a group. Safety first.
Pro: You Can Find Your Perfect Person
Your dating profile will reach a huge number of eyeballs. As such, it behooves you to be specific about what you're looking for. Sites that only show you people who match your criteria feel like bespoke tailoring - you place your order for the perfect person, and they deliver. Sites that allow you to browse through all available profiles are more like off-the-rack shopping - you may find something that looks nice, but it probably won't fit exactly right. Being specific about what you're looking for helps separate the wheat from the chaff - the people who read your profile will self-select to an extent, so the cream will rise to the top and you won't have to wade through a zillion profiles to find the one girl who can spell and doesn't make fish-face.
Con: There's No Such Thing as Perfect
The problem with being specific about what you want is that people tend to have unrealistic expectations. When faced with an Internet-sized dating pool, you may be tempted to look for the millionaire brain surgeon part-time rocket scientist/underwear model who breeds puppies, loves to shop and owns an island. Surely, with all the world to pick from, that person must be out there, right? Well, yes. But that person has no trouble finding dates. And who's to say that this dream-mate who looks perfect on paper isn't an obnoxious jerk in real life? While you're holding out for Mr. or Ms. Absolutely Perfect, you're missing out on a bunch of Pretty Darn Awesomes along the way.
So go ahead, fill out your profile, and jump into the worldwide dating pool. Be fearless but cautious, honest but not needy. You might kiss a few frogs, but your prince (or princess) is out there somewhere.