什么是Call to action (CTA)？
The prompt that tells a visitor what to do next, such as a Start free trial button, and a primary lever for conversion rate.
A call to action (CTA) is the element that tells a visitor what to do next: the "Start free trial" button, the "Book a demo" link, the newsletter form. It is where a page's persuasion is supposed to cash out, which makes it one of the most tested elements in conversion work.
What tends to matter, roughly in order: clarity of the offer (what happens when I click, and what does it cost me), placement (visible without excessive scrolling, repeated on long pages, since scroll depth data shows many visitors never reach the bottom), and specificity of the copy ("Start free trial" beats "Submit"; "Get the checklist" beats "Download"). Button color, the classic A/B test cliche, usually matters only insofar as it affects visibility. One clear primary CTA per page outperforms several competing ones.
Measure CTA clicks as events, but judge changes by completed conversions, not clicks; a pushier button can raise clicks while lowering signups.