Claim to fame:

Freelance reporter, did some freelance work for the New York Times

Current source of income:

Book Evidence of Harm, lots of Huffington Post blog entries

Affiliation:

Thoughtful House adviser. Thoughtful house is Wakefield's current employer.
Huffington Post blogger
Age of Autism blogger (will almost always make an AoA entry after posting something in Huffpo)
Works with Robert F Kennedy Jr

Stance:

anti-vaccine, thinks mercury causes autism, book is very biased with mainly anecdotes and appeals to emotion, very little science.

Defense:

He tends to point at anecdotes and statements by famous non scientists as evidence for his point of view and engage in ad hominems. Brian Deer is a frequent target. Rather than refuting Deer's claims about Wakefield, he attacks Deer by saying Deer must have a conflict of interest.

Frequently lists large numbers of studies and famous individuals as references in his posts, but if you research the links and quotes, they do not actually support his contentions.

Inconsistencies:

Aside from his book's problem with science. He continues to claim that Deer is a complainant in the court case against Wakefield in spite of repeated refutation of this and libel laws in the UK that make it very difficult for journalists there to make claims without a lot of evidence to pack them up.

Dangerous attitudes:

He's a vocal spokesperson for anti-vaccine attitudes. His book encourages the idea that the government is covering up "evidence of harm."

He has a vested interest in keeping the public afraid of vaccines in order to sell more copies of his book, conveniently advertised on his Huffington Post blog entries. He also has a vested interest in defending Wakefield because of his relationship with Thoughtful House.

More info:

Science Based Medicine's Response to Kirby
Kieth Olbermann Played for a Fool