Sherpaa interview questions

I'd emailed one of the founders after perusing the blog. Sherpaa sounded like a very interesting take on an industry/need that's immeasurably difficult. My first interview (might have been a call — I can't remember now) went beautifully. I thought we got along swimmingly, had a great conversation, etc. I was then brought in to meet a senior engineer. The conversations went well enough. I ended up visiting the office for 6 or so interviews, often with little warning to "answer a few more questions." One of these interviews was a reasonably in-depth working session followed by a take-home assignment, all of which I completed and came back to present. After 6 interviews, I was told that an offer was forthcoming and that I'd have it in a couple of days (by the end of the week). The following week I hadn't heard anything and followed up — again I was told that they were ironing out the paperwork, etc. Never heard anything back from them. My follow-ups with both people went completely unanswered. Needless to say, I was pissed. I can handle interviewing and not receiving an offer, but to put someone through the amount of work that I went through and then to promise them an offer — only to drop off the map? That's unacceptable and utterly rude.