Often, when people first start dating online, they get caught up in fantasizing about someone they've seen on the Internet. They're atttracted to the person's photo, think they have a lot in common with each other, and begin picturing themselves in a relationship. This is a dangerous habit to get into.
Because the dating sites now let you monitor how many people have "browsed" your photo, you can get the false sense that dozens of people are actually into you as a person, rather than just your appearance. Then, if that person "winks" at you, you may jump to the conclusion they really do want to get to know you. Be careful about such assumptions. The truth is: a "wink" is a lazy person's way of flirting without having to take the time to write a full, personalized email. He or she is simply saying your photo grabbed his/her attention. No more than that.
It makes no sense (and can be very self-sabotaging) to become infatuated with someone who hasn't taken the time to write you an actual email that mentions something impressive or remarkable about you. In the sender's mind, you're likely to be one of 10 or 20 computer photos he/she winked at that day...not a real flesh-and-blood person with whom to start a relationship. The person is a "kid in a candy store" sending out feelers but not necessarily ready to keep the communication going if those receiving them write back and want to take things to the next level.
Sure, there are some sincere, down-to-earth people online looking for serious relationships. And you can find them if you screen prospects well on email and on the phone. I'm not saying you can't meet some wonderful people for dating. I did, and I married him more than 5 years ago.
What I AM saying is be aware. Know that the larger the dating site, the greater the percentage of possible "cruisers" there'll be (people who enjoy casually browsing nice photos with no intention of actually meeting those folks and very little interest in a long-term relationship). Don't get your hopes up about everyone who contacts you. It could turn out to be no more than a fantasy.
Instead, carefully read the profiles and write ONLY to the people who really wow you and have most of the character traits and values you prefer in a partner. Don't sit back and wait for others to write to you. Take charge and do the choosing yourself. That's what I did, and it worked out great!