What's a Likely Letter from Harvard?

I've been hearing about this 'Likely Letter' from Harvard... Can anyone clarify what this is and how it works?

A Likely Letter is a communication sent by some colleges (including Harvard) to certain applicants whom they are almost certain to admit. This typically happens well before the official decision date, hence the name 'Likely Letter.'In essence, the Likely Letter is the college’s way of saying, “We've reviewed your application, and you are likely to get an acceptance offer when regular admission decisions are announced.” It’s their way of expressing interest in you as a strong candidate for the upcoming class. You might get a Likely Letter based on your early application, athletic recruitment, or other outstanding attributes that set you apart from the rest of the applicants.

It's important to note, however, that while it virtually guarantees admission, it is not an official acceptance letter. You'll still need to wait for the actual acceptance letter to come through during the regular admissions timeframe. But, receiving a Likely Letter is certainly a great indicator of your chances.One thing to keep in mind is that these letters are not sent to all admitted students, so not receiving a likely letter doesn't mean that you won't be admitted. It's also worth noting that Ivy League schools, including Harvard, send the majority of Likely Letters to recruited athletes.