I met my DH through the AOL personals. It's very common now. I do agree that you have to be careful because you never really know but I say go for it. Some things to remember:
NEVER give out your address or phone until you are completely comfortable and pretty darn sure things are headed somewhere. If you decide after many many emails that you'd like to talk on the phone get his/her number, block yours and call him/her. Especially if you have a listed phone number. Triple especially if your address is listed with it.
If the person lives out of town have them come to your town to meet in person. Do not allow them to stay in your house. Meet in a public place, not their hotel room. When you meet have a friend follow you and hang around without the other person's knowledge. Maybe meet up at a coffee shop with your friend sitting at another table to keep an eye on things. Be sure that a second friend knows exactly where you are going, what time you'll be there and what time you expect to leave. Set a certain time to call and check in with them. Tell them once you are 15 minutes late in calling to call the place you are at and have you paged. If you don't answer call the police.
Write down everything they tell you that could help to identify them. I kept track of where DH said he worked, his parents names, his daughters name, his DOB, EVERYTHING. I followed up on all this and it all checked out. When I met with him I gave all that info to a trusted friend just in case. If anything were to happen the police would have LOTS to go on. I was able to do this with a few phone calls and public records on the internet. If you don't find anything it's worth the money to have them investigated. If you cant find info on him he's either dangerous or married. Anyone on the up and up will understand your need to stay safe.
Now, all that being said, *most* people in the personals are looking for the same thing you are and are not dangerous. I think it's a great idea. You may meet your soul mate, you may just meet a few new friends and you may meet a whole lot of duds. Still, it's worth it. I emailed and talked with probably 10 guys, 9 of whom seemed nice and checked out. 1 finally admitted to being married. 8 of them things just didn't quite click and then I met my DH. It was love at first sight and I never answered another email after that. Good luck!