If their profile says they’ve lived in Ohio their entire lives, but they’re using non-standard English, or have notably poor grammar, that could be a warning sign (think of the kinds of errors you’d see in a Nigerian scam email or on the phone, where they need to spontaneously come up with things to say. Obviously, there are plenty of non-native speakers out there who are sincerely looking for a relationship, and they could very well be from heritage speaking communities in the United State or Britain.
This isn’t a dead giveaway, but it’s something to watch out for.
Of course, some people are just shy or are nervous about meeting people that they’ve met online—this isn’t anything out of the ordinary (it’s also possible that they’re trying to avoid getting caught by a spouse The Ashley Madison dating site was recently hacked by hackers who threatened to leak the entire database unless the site closed. Asking for any other financial information—where you bank, anything about your credit cards, how much you have in savings—should be a big warning sign.
They might also say that they live near you, but that they’re away; they could be in another country on a trip or for work, but they’ll almost certainly be somewhere far away where you can’t meet them.
The photos used by scammers can also clue you in that something is off.
It’s possible that it’s someone looking for an affair on a dating site The Internet seems ecstatic about the Ashley Madison hack, with millions of adulterers' and potential adulterers' details hacked and released online, with articles outing individuals found in the data dump. Even if someone’s profile looks legit, there are other signs to keep an eye out for, especially during the beginning of your communication.
For example, scammers will often ask you to communicate with them outside of the dating site—via email, through Facebook, or even on Skype.