I don't believe so. . . which probably means that it exists in one form or another and therefore is part of the algorithm, so he cannot comment on it. Just a guess, FWIW.
My site (all manual, original content) was sandboxed/filtered/whatever for ~4 months. It was doing very well in the index for a month or so after launch (until late January) and then completely disappeared for its main keywords until about a month ago. It is in the travel industry and my main keywords are CITY name and CITY REAL ESTATE.
Since launching the site, I had been adding original content on a daily or weekly basis and getting inbound links at the rate of around 3 per week, concentrating on PR4+ on-topic non-reciprocals. I tried LSI to no apparent affect. I gave up and did nothing for 2 months.
Then after reading about Hilltop I started to buy links from my competitors, starting in real estate.
Boom! My site suddenly appeared for CITY REAL ESTATE around #100. Bought more links from competitors. Page 3. Bought a link from the #1 site, rose to #3. Just bought one from the #2 site and am waiting the outcome. Did the same thing with just CITY name. Suddenly appeared at #125. More direct competitor links. . . #24. A few more, and now I am finally sitting back on Page 1 for CITY name after 5 long months.
Note: I had been getting on-topic links before, but even though they had decent page rank, the other sites' pages were not ranking for my terms. I had a PR6 and around 30 inbound links not counting my own pages. It seemed to make all the difference getting links from sites ranking for my terms and then getting more links from sites ranking above me. And it happened quickly after getting each such link. A few were reciprocal links, fyi, but the majority I had to pay for. I hadn't changed anything else on my site for 2 or 3 months. It looks like you can just buy your way to the top, and the formula looks pretty straightforward.
Note 2: My site was (and still is) in the top 5 results in Yahoo for just about every phrase I target. It's now on page 1 in Google for just about every phrase except CITY HOTELS, for which I plan to start buying my way to the top this afternoon.
I hope this helps some people stuck in the "sandbox". I still believe that this is a Hilltop-type filter that keeps sites out until they get links from authority sites for their keywords, but that's just my $.02 . Well, I guess it's also based on first-hand experience ;¬)