There's no arguing that Facebook is wildly popular right now.
Years ago, when Facebook was limited to only Ivy League students, it was somewhat popular but not like this.
Then, Facebook allowed students from other universities and colleges to join.
At that point, Facebook still had a smaller user base than MySpace.
Then Facebook allowed high school students to join, and then finally the general population.
This made all of the difference in the world.
Once Facebook became an option for everyone, people flocked to join.
This could have backfired, if it had caused a negative reaction from users who enjoyed the previous exclusivity.
Instead, it just made the site more popular.
Facebook keeps its popularity up through several factors: Everyone has a Facebook.
Eventually, Facebook's popularity became so vast that there are now more people who have a Facebook account than people without one.
People who don't have a Facebook are socially disadvantaged; they may miss out on communications from friends and family and so on.
Facebook also is much better than MySpace at merging business users and individuals.
Facebook allows entrepreneurs and businesspersons to link with individuals who are interested in their fields or products.
No awful ads.
Facebook ads may be repetitive, but they are not overly flashy or vulgar like the ones you see at MySpace.
Facebook also targets advertisers to each user, so you will be seeing ads on things you are interested in and you may even find a valuable product or service that you can use via the ads.
Great games and apps.
As Facebook users know, the site features online games for every taste.
You can pretend to be a Mafia member, tend a virtual farm, take care of virtual pets, and on and on.
These games reward regular players with points and virtual awards or new levels.
Because the more you play the more you are rewarded, this keeps Facebook users coming back and logging in.