Let me say first of all that I have great respect for the way you have engaged with criticism on this post and on your previous ones. Even when I disagree with your approach or whatever, I appreciate your curiosity and eagerness to learn.

Some ways that you could make weaker claims but with more confidence in your results:

* Have an unordered list of companies that are growing. This was your suggestion. I don't know how interesting that is.

* Group companies into five or ten buckets, based upon Alexa ranks. (i.e. 1=low traffic bucket, 5=high traffic) Find the top three movers-and-shakers within each bucket. This makes the weaker assumption that Alexa ranks deltas are comparable within each bucket, as opposed to your original assumption that they are comparable across the entire spectrum of Alexa ranks.

There are a handful of other things you can do that are more complicated. For example, if you can correlate Alexa ranks with Compete unique visitor estimates or some other number (company's exit value). Compete estimates are also biased, but at least people have better intuition of what unique visitor numbers mean.