I used to work in the keynote speaking industry as an agent. This industry is horribly inefficient and intentionally so. It's mostly east-coast based - NY/DC but functions similarly to the LA entertainment industry. The main problem is this: You are a meeting planner (not your job title, you are actually a marketing person or executive assistant) and your boss just tasked you with find a speaker for your next company…
There are marketplaces for speakers: espeakers.com, orate.me, bigspeak.com, kepplerspeakers.com, speakermatch.com, eaglestalent.com, celebrityspeakersbureau.com, among others. The speaker profiles include prices, areas of expertise, and a way to inquire and book. What they don't show, that you're asking for, is speaker availability and popularity. The problems I see with disclosing the schedules of speakers: 1) celeb…
Bigspeak, Keppler, Eagles Talent, and Celebrity are bureaus and function in a traditional way. Espeakers and SpeakerMatch are essentially speaker directories -- they make money from speaker's paying them a monthly fee or in a lead gen style.
Orate.me is new to me, I haven't seen it before. In a cursory look at their site, it looks like their speaker list is just NSA members.
Also the calendaring problem is easy to solve...
There's enough public data to develop a sentiment algorithm and solve the popularity problem.