There is a big difference between a talent agent and a recruiter. A recruiter ultimately works for the company needing talent and has the needs of their client companies. An agent works for the talent and will scout out the most promising opportunities (pay well, interesting work, work that leads to greater opportunity).

I wouldn't say it's new persay but I don't think they're quite recruiters. I generally think of recruiters as being paid by a company to find employees rather than the payed by an employee to find companies. Both agents and employees act as the middle man for the same transaction but they represent different people's interests. It's new in that this it's just now becoming the case that programming talent is valuable enough that 15% of it can actually buy a full time employee to represent the employees interests.

I've never met a recruiter that works in my interest. Maybe I haven't met enough recruiters?

Recruiters trying to hide behind the name 'Agents'. They don't add any value instead headache for developers. I would recommend staying away as far as possible from these so called 'agents' who just want your 15%.