20bits

San Francisco, CA Hi HN! I'm Jesse, one of the founders of Everlane. http://www.everlane.com We're trying to re-imagine retail online and make it easy to find products that match your taste and style. Right now we're focused on mens fashion, but our ambitions are much larger. pg did a good job of explaining the opportunity, here: http://ycombinator.com/rfs2.html We're building a members-only club where each month we produce and release a new collection of mens accessories and apparel. Yes, we're selling our own products, directly to consumers. This lets us offer a tie you'd buy for $80 at Nordstrom's for half that. To produce in-style products we have a team of curators, run the largest men's fashion Tumblr, and are generally data-savvy people. You can read my (somewhat out of date) blog, here: http://20bits.com We're well-funded by the most stylish investors around. We offer competitive salary, equity, and benefits. Our office is in Union Square in San Francisco, CA. If you're a hacker, love data, and/or love style shoot me an email at [email protected] and get in touch. Also, if you're up to the challenge, here is a little exercise for you: http://static.everlane.com/everlane_exercise.pdf

First thing on duckduckgo when you search for how to write a server in erlang: http://20bits.com/article/erlang-a-generic-server-tutorial That's just ridiculous. Erlang looks like php and python had an unholy child.

This blog post seems to be copied from http://20bits.com/articles/graph-theory-part-iii-facebook/ without any attribution. It was also posted on yc only two weeks ago (see http://news.ycombinator.com/item?id=2912073 for commentary).

It does, but the link is broken. You can find it here... http://20bits.com/articles/network-programming-in-erlang/

His direct links from part 3 to parts 1 and 2 are broken. However if you click on "More Articles" (http://20bits.com/category/articles/) on his homepage the links there work fine. http://20bits.com/articles/graph-theory-part-i-introduction/ http://20bits.com/articles/graph-theory-part-ii-linear-algebra/

An interesting supplemental reading is the "two bowling balls" interview puzzle -- http://20bits.com/articles/interview-questions-two-bowling-balls/ It's essentially a 2 level skip list (but could be generalized where you get one extra level per bowling ball), and brings out some basic calculus to optimize lookup performance even further.

This, of course, is a popular interview question, albeit asked with eggs (or bowling balls) instead of cats. Here's a discussion and a solution: http://20bits.com/articles/interview-questions-two-bowling-balls/. I think for m balls and N floors, the number of steps is O(N^(1/m)).

> Basically, "the more the better". Actually, no. Too much shuffling actually makes some sequences less likely. See http://www-stat.stanford.edu/~susan/courses/b494/index/node109.html For some simpler math for a related question, see http://20bits.com/articles/interview-questions-shuffling-an-array/

A point to add to the discussion from the metrics perspective: the net promoter score. Net promoter score is an easy tool you can use to determine trends in your users' experience. It can be used as a leading indicator of the 'N' part of your viral coefficient. eries goes in to detail in "Net Promoter Score: an operational tool to measure customer satisfaction" (http://startuplessonslearned.blogspot.com/2008/11/net-promoter-score-o… Additional reading from HN members: jfarmer's "Three myths of Viral Growth" (http://20bits.com/articles/three-myths-of-viral-growth/)

Although in the image, nowhere could I see p value, I have verified it by myself that there is 95% significance. And I agree with you it depends on perspective on what you consider significance. BTW, those wanting to know the math head to http://20bits.com/articles/statistical-analysis-and-ab-testing/

I think there was an error in his analysis of the naive solution for finding loops in linked lists (at http://20bits.com/2008/04/17/interview-questions-loops-in-linked-lists… I don't know Ruby, so correct me if I'm mistaken, but I believe the naive solution presented runs in O(n) space and O(n^2) time (not O(n) time, as the author suggests). If you used a hash table to keep track of nodes seen so far, you could do O(n) time and space. The tortoise and the hare solution is quite elegant though.

I've never really paid attention to this field, but I just tried the sample queries from http://20bits.com/2008/05/12/powerset-launches-verdict-meh/ in Hakia. As far as I can tell, Hakia only answers the last question correctly without having to dig through the results.

Here's the full report linked to in this article. http://20bits.com/2008/05/06/the-state-of-the-facebook-platform/

"... An important tip, not mentioned in the article: 'blog about Web 2.0 aimed first and foremost at programmers, computer scientists, and mathematicians' ..." Looked at the site, interesting ~ http://20bits.com/2007/04/27/facebook-job-puzzles-prime-bits/ Maybe they are paid to code, but not to think "why"?