The Internet allows us to search for and communicate with people from all over the world, regardless of their proximity to us.
Some of that feeling is a result of the disinhibition that's a part of being anonymous on the Internet today.
So go slowly with new contacts and get to know the person via messaging and emails first.
Be Realistic Prince (or Princess) Charming may very well indeed be waiting for you online, but you should also set your expectations just a little bit lower. Don't believe that everyone who shows interest in you is worth your time.
And don't get disenchanted if your first date decides they don't want a second.
Don't feel the need to give out your phone number if you're not comfortable doing so.