Editor’s note: Bryan Urbick is founder and chairman of Consumer Knowledge Centre, a London research firm.

So much is being said about the influence of social media, particularly Facebook, and how it is the new marketing frontier. I can appreciate the interest in it – it is new, it is widely available and it is popular.

Importantly, though, we need to get down to the kernel of what social media is about – and here we will find the “F factor” – how friends, fans and followers impact what brands are about.

Following and being a fan are behaviors that have been done for decades. The idea of keeping up with people we are interested in is not new. Newspapers and magazines had the original, most popular remit, then radio, then TV and now social media (it makes me wonder, what’s next?).

What has become so powerful with new media is that it is initially popular and easy to follow so many more individuals and get the feeling that you are getting the more personal, inside scoop. The trouble, though, is how tiring it is to follow so many more people. The wear-out ultimately causes less usage.

There is a saturation point – and perhaps this can be stretched from more traditional media, though there is a limit to what people will follow, how much time they will spend and for how long they will be intense.

The voyeurism, though initially compelling, loses its luster. And when brands and products try to live in this world, it is difficult. How long can a brand sustain high levels of interest, when celebrities (who happen to be “real” people) can’t keep the interest sustained?

Friending is an even older behavior. Who doesn’t want a lot of friends? Though at first the answer may seem to be, obviously, everyone, the truth is somewhat different. Most of us do want good and close friends – but as with all relationships, friendships need to be nurtured and developed. The reality is that we have limited time to build and sustain genuine friendships – and it takes work! We can’t assume that posting pictures and offering updates (to the masses) will foster genuine friendship – real friendships require depth, a personal understanding of each other’s needs and the desire to continue the relationship.

Though Facebook and other “friending” may be popular, the term “friend” should actually be “acquaintance” for the depth of the relationships. And though it may feel nice to have more “friends” than others, that popularity is childish, reminiscent of the “popular in school” syndrome that is not usually lasting.

And for brands and products, it is still quite abstract to be a friend – though arguably there is at least more real interaction with many brands and products than the superficial layer of friends on social networks.

Against this backdrop, what are we to make of Facebook’s apparently waning popularity? Recently, according to tgdaily.com, even though Facebook is the most widely-used Web site in the U.S., it has a lower satisfaction level than that of the Internal Revenue Service’s e-filing sites.

Further, according to the 2010 American Customer Satisfaction Index (ACSI) E-Business Report, produced with ForeSee Results, Facebook scored 64 on the ACSI’s 100-point scale – putting it in the bottom five percent of all measured private-sector companies (in the same score range as the typically unpopular airlines and cable companies).

Here in the U.K., the British Broadcasting Corporation has reported as far back as 2008 that Facebook was showing signs of decline. While not occurring every quarter, the intermittent drops, albeit small, may be showing Facebook’s vulnerability.

The real question is not, “Will Facebook survive?” but rather, “How will Facebook evolve?” My crystal ball is a bit cloudy in this regard, but I do know that to thrive, it will need to evolve and remain relevant – and so will brands and products that want to hop on the social media bandwagon and benefit from it.