Once on top, it's hard to stay there. As other social networks can stand by to that statement, Facebook seems to be ignoring all critics that see its death in the hands of its own success. As the network reached a ground-breaking number of 325 million users, the company seems to be on track to reach the goal it set in May of this year to achieve the 500 million users mark.

The service did not only take its goal seriously, but it came under par when supplying the tools and applications to keep their users interested and attract new ones. Facebook has constantly gotten better, upgraded its services and paid close attention to the details that previously ruined or brought down other social network juggernauts: real users on the site.

There is no point in proving that MySpace, Bebo or Hi5 are full of spamming bots and fake users that make your life a living hell whenever logging in on one of those services. This fact has now become common knowledge. And studying the cases of other social services, Facebook has taken all the right steps in keeping the mass of all those bots out of its service.

This is why the 325 million mark is such a big thing. For the biggest part, there are over 300 million real users on the website. Only by flipping through the official statistics page on Facebook, we see that about 50% of those users log in every day on the network.

Another measure of its success is the fact that about 70% of all users using the network are from outside the United States. With a balanced user base, the service has again surpassed networks like MySpace that only made it really big in the US, or Hi5 that is big in Latin, Eastern European and Hindu regions.

The thing to watch now: Facebook - 400 million users.