— Perfectmatch's Duet ® Compatibility System is one of the most comprehensive and reliable compatibility systems available.

— It searches for highly compatible matches based on your Duet profile, and it emails you when a match is found.

— You can use their comprehensive tools to search user profiles and initiate contact, which allows you to choose only the matches that are right for you.

— Members can seek advice from professional relationship experts including Dr. Pepper Schwartz, the co-developer of Duet ® Compatibility System.

In a league by itself, Perfectmatch delivers one of the highest user satisfaction rates. It is the fastest growing relationship service in the U.S. You'll have higher chance here than anywhere else to find your desired match.

Perfectmatch has been featured on numerous TV shows and major motion pictures.

— You can create and publish your full profile with pictures for free. This will allow you to search for matches, view others' full profiles with pictures, and send winks.

— Paid subscription will give you full access, including the ability to communicate with others through IM and email.

— You'll be able to see who's been viewing your profile. People in this list are likely already interested in you.

— You'll get a dedicated mailbox so you can wink, email, or flirt with anyone at any time, safely and privately.

— You can quickly find people with common interests using its one click search feature called MatchWords™.

Match.com offers more online features than any other dating service. It also inspired twice as many matches as any other dating site.

It is the world's largest online dating service with more than 20 million members worldwide, according to Guinness World Records.

If you sign up for a 6 month subscription and end up not finding someone you like, Match.com will give you an additional 6 months for free.

— Chemistry.com's compatibility matching system is a next-generation technology which is based in part on the science of brain chemistry.

— Offers free Personality Profile, which is reasonably short and tells users what personality type they predominantly are, and therefore which other personality types they are best suited for romantically.

— Chemistry's First-Meeting® Technology will help you prepare when you decide to meet someone face-to-face for the first time.

Chemistry's Compatibility System and Personality Profile are regarded for their accuracy and are among the best. It is one of the fastest growing relationship sites in America.

Chemistry.com uses both hormonal-based and personality-based matching techniques.

Chemistry has been successfully targeting people who have been rejected by eHarmony. You'll be very satisfied with their really impressive service.

— Yahoo offers anonymity, safety, and security up to the point where the user is willing to reveal his or her personal information to someone else.

— Yahoo! Personals' search technology highlights more relevant potential dates than most dating services. You can search for a person who is already looking for someone exactly like you.

— It shows you who's been looking at your profile. You'll enjoy this feature as people in this list are likely already interested in you.

— If you create a free profile, you'll be able to search, view full profiles of others, and send icebreakers for free.

You can enjoy the benefits of full membership totally free for 7 days through this special link. This will allow you to communicate with the others.

Yahoo! Personals has been achieving the highest customer satisfaction rating recently among the major online dating services. Unlike most other dating services, it lets you search and view others' full profiles with pictures.

Yahoo! Personals is one of the most effective dating services for meeting local singles.

— Its Guided Communication feature helps you break the ice without the awkwardness when you find a match and want to communicate for the first time.

—  Its Open Communication feature allows emailing each other through eHarmony's anonymous message system until you're ready to share your personal information.

— eHarmony protects the identity and anonymity of its members until they are ready to share personal information with someone they want to know better.

eHarmony is targeted towards individuals who are genuinely seeking long-term relationships. On average, more than 236 eHarmony members are married every day in the United States.

It is one of the largest dating sites with 15 million registered members.

eHarmony's services are selective. You'll be rejected if you are married, under age 21, homosexual, or provide inconsistent answers in the 500-item personality questionnaire.

— Offers 3 exciting communities: Dating (for finding dates and flirting), Relationship (for finding romance), and Intimate Encounters (for exploring your wild side...)

— You can search for like minded singles by age, location, religion, interests, and more.

— Lets you send unlimited emails, start unlimited instant messaging sessions, and contact as many members as you like with your membership.

Lavalife is a hugely popular dating service with over 15 million members worldwide. You can create 3 unique profiles for each of its 3 communities - Dating, Relationship, & Intimate Encounters.

The third community ventures into adult territory, and you can have more adult sense of fun.

Since members can respond for free, Lavalife members get more replies than any other dating sites.

— It's free to join and create an account.

— SinglesNet has an extremely quick sign up process - about two minutes in total.

— It provides all the basic and advanced features available in other dating services.

— Free membership gives you access to all of the normal SinglesNet features, including contacting other members and using compatibility matching system.

SinglesNet has over 5 million members and it's growing very fast. Its free membership service gives you access to more features than any other free dating services.

Being able to initiate contacts with your potential matches without having to pay or use credit card first is really outstanding.

— You can create a free profile, upload pictures, and receive emails from other members at no cost.

— You'll receive help in creating a great profile that will attract a lot of singles.

— Offers instant messaging with voice and video greetings

— You can perform search by age, location, interests, hobbies, and more personal preferences.

Founded in 1986, MatchMaker.com is the oldest of the current online dating services. MatchMaker nicely aligns its members into one of several demographics.

Instead of giving you a personality test, MatchMaker lists questions on major issues that draw a general picture of who you are. So you'll spend less time filling your profile.

— You can create a free profile and upload pictures at no cost. Paid membership allows you to communicate with others.

— Offers all the basic and advanced features available in most dating service.

— You can perform search by age, location, interests, hobbies, and more personal preferences.

Established in 1997, Date.com is one of the oldest internet dating services. It has more than 2 million members. If you live in a large city, you'll be able to find lots of local singles.

This service is geared toward serious daters who are looking for long-term relationships.

— This is an exclusive service offered by Perfectmatch for singles over the age of 40.

— Its Duet ® Compatibility System searches for highly compatible matches from singles age 40+ and emails you when a match is found.

— Members can seek advice on online dating after forty from professional relationship experts including Dr. Pepper Schwartz, the co-developer of Duet ® Compatibility System.

Perfectmatch created a popular community for mature adults. Currently it is the best online dating service for singles over 40.

If you want to meet someone over 40, you can comfortably choose Perfectmatch.

Perfectmatch is featured on "Another Chance for Romance" - the first dating show focusing solely on seniors.