Its a database of traders, trades and the experience of the two traders with each other.
For example, if u click on my
heat here, u'll see a list of people who've traded with me. By clicking "Open" u'll be able to see the other's comments about me & the trade. If u click on the other's name, it'll open up his evaluations.
Heat is essential if u want others to trust u and/or ship first.
If u're a newbie trader, remember these simple rules:
1. If someone with considerably more heat than u wants u to ship first, u should ship first. Howver, make sure that u e-mail them at the e-mail address provided in the heat page AND the e-mail address listed on his Anandtech profile and wait for replies from them before doing anything.
2. Check the bad traders database for his name & shipping address.
3. Get a telephone number and call him up if its a hi-value trade
4. Communication is key, never let it drop
5. E-bay evals aren't worth diddly ... I dont mean to offend anyone with ebay evals, but trolls have used them time & again to sucker n00bs
6. IF u get a bad feeling about the trade, back off