Everyone has heard about Facebook, Twitter and LinkedIn. The appeal of these sites is that almost everyone is welcome.
But did you know there are other digital communities that cater to smaller and more unique groups of people?
Below are a few of the more interesting or stranger social networking sites. Tell us your favourite and which one you'd most like to join.
If you're a fan of karaoke, forget making a trip to a bar or owning your own game console. Practice your favourite tunes instead with people around the world, using Red Karaoke.
The app, free on iOS and Android, has an easy-to-use interface and backing music with professional quality. Users can also make their own video recordings as well as view other ones made by people around the world.
You can also change the key of the backing track when singing along to match their voice as well as the lyric's font size.
However, it is not entirely free as songs cost credits. After the first 250 free credits you get for signing up, you need to sign up to a monthly or annual subscription.
aSmallWorld is an invite-only social network for the elite. Launched in 2004, the community connects users who belong to the same social circle and keeps everyone else. Anyone who wants to join has to be invited by a current member and fork over an annual fee of €85. Labour frontbencher Chuka Umunna admitted he was a member of the site under a pseudonym earlier this year. Perks include deals, discounts and special access from hundreds of partners including airlines, hotels and spas.