Ask HN: Should I buy email list or not?

https://news.ycombinator.com/item?id=7842282 - On this above thread, there is lot of motivation for founders to focus on sales. Cold calling is also favored so why not buying email lists? Generating your own email list is a great thing but it is slow and takes times.

So, if sellers can assure you source of email list, type of people and how recent the data is - will you buy it or recommend to buy it?