Can you explain the process by which Estibot values domains?
 I have noticed that some of my Namejet domains, which I do not consider to be of significant value, are valued by Estibot for much larger sums. For instance, Estibot values "eradicator.com" at $3,719 USD, "mathteachers.com" at $1,400 USD, and "bleedingheart.com" at $7,498 USD.

However, some of my short one-word dictionary domains are not evaluated by Estibot at all, even though they have potential value. Additionally, I had been considering purchasing the domain "gymitems.com" for some time, which refers to sporting goods, and Estibot had initially valued it at $620 USD. But when I decided to buy it, the value had increased to $2,100 USD. How did its value increase by 3.5 times?
What did the current owner do to achieve this?

Based on my experience, buyers typically do not pay attention to these virtual estimates. When I bring up services like these to buyers, they often respond with something like, "I'm not interested in that." It seems that these services are mainly utilized by sellers as a way to deceive buyers or boost their own egos. Additionally, I've noticed that Estibot's evaluations are not always accurate - some domains that it values poorly end up selling for high sums, while others that it values highly do not sell at all.

When it comes to how these estimates are calculated, it's important to read the information provided on the evaluation page. The calculations take into account recent sales of similar domains, competition, advertising bid prices, and more. However, these calculations can often be unreliable - just one character can make a huge difference in the value of a domain.

In my opinion, both buying and selling based on these estimates is foolish. These websites are primarily for entertainment purposes and should not be relied on for accurate valuations. End users typically do not take these assessments seriously, but some domainers do.
However, if Estibot actually purchased domains at a percentage of their valuation price, their evaluations might hold more weight. As it stands, these services primarily serve to boost domainers' egos. My advice is to avoid wasting money on them.

Estibot uses a variety of factors to determine the value of a domain, including the length of the domain, the popularity of keywords in the domain, the extension (such as .com, .net, etc.), the search volume for the keywords, and the number of comparable sales.
In the case of your Namejet domains being valued at higher sums than you expect, it's possible that Estibot is assigning value based on the potential usage of these domains for specific industries or businesses. For example, "eradicator.com" could be valued highly due to its potential use in pest control or security services, "mathteachers.com" could be seen as valuable for educational resources targeting math teachers, and "bleedingheart.com" might be considered valuable for charity organizations or health-related services.

On the other hand, your short one-word dictionary domains not being evaluated may be due to the fact that Estibot has less data on similar domains to base its valuation on. It's important to note that domain valuation tools like Estibot are not infallible and may not accurately reflect the true market value of a domain, especially for unique or niche domains.

Regarding the increase in value of "gymitems.com", there could be several reasons for this jump. The current owner may have improved the domain's SEO by creating relevant content, building backlinks, or increasing its online presence, all of which can influence its perceived value. Additionally, market trends and demand for domains related to certain industries can fluctuate, leading to changes in valuation over time.