No need for the person with asthma to end up on a date with a chain smoker.
Online dating can save you from some of the obvious mismatches, at least.
Search Tools Each person values different things, but if you know you are not compatible with anyone under or over a certain age, for example, you can filter for that.
The best services allow you to see things like how often people log onto the site.
A dating site should act as a kind of screening tool, helping you find people you may like, and helping to protect you from anyone dangerous.