Dating online can be successful, but it takes extraordinary measures to ensure it goes well. Your mental health must be in good working order for starters. I have a very good friend who met someone online, but she approached online dating as entertainment instead of putting all her emotional energy into the search. She had a formula that worked for her so she didn't get emotionally attached, but she still did have a lot of unpleasant encounters as well.
She is in a happy relationship now with someone she met online, but she didn't have any expectations. Her formula was to get to know someone through texting and eventually a phone call to better understand their intentions. Only when she was comfortable with their interactions would she agree to meet. There were some men that she met that tried to rush her. She knew that they weren't thinking clearly, and quickly put them in the infamous friend zone where she started with everyone. Instead of allowing lust to control her thoughts, she tried to see if she was genuinely attracted to her potential partner first.
Her method was effective because she is logical and her mental health is impeccable. It doesn't work for everyone. I, myself, do not enjoy online dating. I have an active imagination and can create some pretty wild scenarios in my head, but this fantasy-thinking gets me into trouble. I had to stop. I would rather meet someone in person out doing something I love where I'm already producing happy chemicals, than live in a fantasy world.
There are pros and cons to online dating, and dating people you meet out as well. If I could give anyone one piece of solid dating advice it would be, just get out and live. Go dancing, sing, help people in need. But most of all don't take life so seriously.