Millions of potential mates are just a click away on Internet dating sites. Here are 4 of the most popular, by the numbers.

By Real Simple
Updated January 14, 2010
Bio photo of a fiance
Credit: Andrew McCaul

Price: Free.
Users per month*: 2.75 million.
Registration time: 12.5 minutes.
Pros: Costs nothing; easy to use; has a huge pool of people to flirt and connect with; boasts 120,000 marriages a year.
Cons: Distorted or fuzzy images; unattractive website.

Price: $30 per month.
Users per month*: 2.75 million.
Registration time: 15 minutes.
Pros: Simple to navigate; finds matches based on keyword descriptions; provides apps for smartphones.
Cons: Poor screening techniques.

Price: $50 a month.
Users per month*: 2.5 million people.
Registration time: 10 minutes.
Pros: Safer than some sites, since members must submit to a background check; has a fun, flirty environment.
Cons: Tacky advertisements.

Price: $60 a month.
Users per month*: 1.75 million.
Registration time: 25 minutes.
Pros: They do the matching for you, based on a detailed questionnaire; an advice section with expert and member tips.
Cons: Generic profiles; more expensive than other sites.

*The numbers for users per month are based on research by ComScore.