While blogs have been around for a while, and the internet has been in use by the public for almost two decades, there's been a lot of recent proliferation of high-speed internet in offices and homes that maybe was not as common four years ago, and there's been a real boom in user-produced content.
Blogs are doing a more sophisticated version of what chain e-mails have been doing for years; dispersing questionable information to a whole lot of eyeballs. This has been used to the detriment of both party nominees:
Barack Obama's wife Michelle has been hit with rumors that she made a derisive reference to "whitey" while participating in a Trinity church panel discussion that included divisive Nation of Islam leader Louis Farrakhan.
This rumor seems to have been a blogger named Larry Johnson who claims to have some unnamed friends who swore to have seen Michelle make these statements on videotape. But as, neither the friends nor the video have been forthcoming it's significantly likely that no such panel discussion ever occurred and that Mrs. Obama never said anything like that.
A similar accusation has dogged Republican nominee John McCain. Writer/blogger Cliff Schecter reports that he has anonymous sources who told Schechter that McCain called his wife Cindy a "cunt" in response to a joke she made about his thinning hair in 1992.
Both attacks rely on anonymous sources. If you ask Johnson or Schecter to verify their accusations, they will tell you that they are relying on the credibility of the sources, and if you ask who the sources are, then the writer is sworn to secrecy on the subject.
It's a mechanism rife for abuse, which is why newspaper and magazine editors have exacting policies on citing to unattributed sources, including independent corroboration. And a reputable newspaper will be very sure it trusts a reporter before it publishes a story by that writer containing unsourced claims. And readers generally know, within reason, which publications they trust not to intentionally promulgate lies.
Blogs have no such safeguards. Johnson and Schecter respectively could have fabricated these claims. No person alive will publicly claim to have heard John McCain call his wife a "cunt" or to have heard Michelle Obama refer to "whitey."
Barack Obama had to dedicate a whole section of his website to fighting the lies and questionable claims people keep making about him. McCain, whose out-of-context soundbites have been fodder for plenty of YouTube videos, will probably add a similar section soon (especially since his website has been redesigned to resemble Obama's).
You also have to wonder what the deal is with blogs who will excoriate one of these unsubstantiated viral smears while promulgating the other. Shame on the authors who publish these attacks and the bloggers who spread them.
Being better and being right means you don't have to lie about the other guy or misrepresent his positions.