I have a freeware hosted on my website, and use webalizer to track the traffic. I can get the data of my installation file from webalizer in section "Top 10 of 583 Total URLs By KBytes" (till Jan. 23):

• Hits: 21753 (6.45%)
• KBytes: 40150088 (91.27%)

The size of installation file is 6564989 bytes, suppose it's 6565 Kbytes. Then the total downloads can be simply calculated as:

40150088 / 6565 = 6115, convert to weekly downloads will be 6115 / 23 (till Jan. 23) * 7 (days/week) = 1861.

Now comes with my questions:

• What does the 21753 Hits mean? 2/3 of the hits failed or people using multi-thread download tools?
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No - the "Top URL's by KBytes" statistic is compiled from total KB downloaded, not from total completed downloads - this means that five people who downloaded 20% of the file would be counted as 1,313 KB each (and, in total, those five people would count as 6565 KB) ... but 20% of the download across five different users does not equate to one full download in practice.

What does the 21753 Hits mean? 2/3 of the hits failed or people using multi-thread download tools?

21,753 hits means that the file was requested from your webserver 21,753 times - webalizer makes no distinction between human and bot traffic here, and a single visitor may very well be issuing multiple requests against the file.