I think the biggest challenge for most people is "jumping the gun" or emotionally investing into relationships too quickly.
A profile is one of two things. If it's yours it's a "Help wanted ad" and if it is another person's then it's a "resume". Most companies take their time and interview (several candidates) as well as do a background check on those they are seriously considering before making a job offer.
(At the end of the day we are all responsible for our choices in life.) Each of us gets to choose our own friends, lovers, and spouse.
The Internet/online dating is nothing more than an option or (tool) for meeting others. Much like a fork it can be used to eat a garden salad or a slice of double fudge chocolate cake. However I have never heard of an overweight person blame their weight gain on a fork! And yet people blame their bad dating experiences on the Internet/online dating. We make our own choices.
The same people that are online go to the grocery store, movie theatre, beach, park, nightclubs, shopping malls, and church. It's not where you meet but whom you meet that counts! The Internet did not invent liars and cheaters. It's important to use good "commonsense" when dealing with strangers no matter how you met them.
Awhile back I wrote a hub titled: 6 Common Mistakes Women Make With Online Dating. (Men make the same mistakes). http://hubpages.com/relationships/6-Common-Mistake...