Startup accelerators provide funding, mentoring, and networking opportunities to early-stage companies over the course of 3 months. They help accelerate business development and connect founders to investors. Example programs include Y Combinator, which offers $11,000 in funding and takes 2-10% equity, and the German Silicon Valley Accelerator, which offers $20,000 in funding without taking equity. The document discusses the purpose and value of accelerators, as well as examples of common accelerator models.