Conventional teen wisdom: once your parents embrace something, it is no longer cool. So, inspired by a recent Facebook friend request from my mother, I am boldly declaring on this blog that Facebook is so over.

With Facebook’s rapid growth, (More than 200 million active users), it was only a matter of time before it reached a critical mass and spread to the squares… and even the technology-impaired, like my mother.

The numbers back this up. According to the Inside Facebook blog, the number of Americans over 35 on Facebook has nearly doubled in the past two months alone, now compromising 30% of users. Of those, the fastest growing demographic is women over 55. Pulling back a bit, there are now more users old enough to have kids (ages 26-65) than there are kids (ages 13-25 – Facebook forbids users younger than 13) on Facebook.

Will the adult presence on Facebook have a chilling effect on the lewd behavior conventional wisdom says teens chronicle online? Perhaps. And if it’s no longer safe for a teen to post compromising photos of alcohol consumption and obscenity filled wall-postings, where will they turn for their daily debauchery? Twitter perhaps?

Perhaps not, according to Reuters’ MediaFile, Twitter’s recent rise in popularity is due to adults:

But Twitter devotees are grayer than one might expect: The majority of Twitter’s roughly 10 million unique Web site visitors worldwide in February were 35 years old or older, according to comScore.

In the U.S, 10 percent of Twitter users were between 55 and 64, nearly the same amount of users as those between 18 and 24, which accounted for 10.6 percent of the total.