Blog
- 289Oct 16, 20181 minmarketing
What are CAC, LTV, and PBP in Marketing?
What are CAC, LTV, and PBP in marketing? CAC (Customer Acquisition Cost), LTV (Customer Lifetime Value), PBP (Payback Period). The LTV:CAC ratio helps you determine how much you should spend to acquire a customer for sustainable growth.
Read more → - 290Oct 13, 20181 mincommunication
Nonviolent Communication (NVC)
Judgments and violence are tragic expressions of unmet needs. Nonviolent communication can improve communication quality by valuing everyone’s needs. It is NOT about being nice or making others do what we want.
Read more → - 291Oct 9, 20181 minsystem designdata structures
Bloom Filter
A bloom filter is a data structure used to detect whether an element is in a set in a time and space efficient way. A query returns either "possibly in set" or "definitely not in set".
Read more → - 292Oct 9, 20181 minsystem designdata structures
Skiplist
A skip-list is essentially a linked list that allows you to do a binary search on. The way it accomplishes this is by adding extra nodes that will enable you to ‘skip’ sections of the linked-list. There are LevelDB MemTable, Redis SortedSet and Lucene inverted index using this.
Read more → - 293Oct 9, 20181 mindata structuressystem design
Skip List
A skip list is essentially a linked list that allows for binary search. It achieves this by adding extra nodes that enable you to "skip" parts of the linked list. Given a random number generator to create these extra nodes, a skip list has O(log n) complexity for search, insert, and delete operations.
Read more → - 294Oct 9, 20181 mindata structuressystem design
Bloom Filter
A Bloom filter is a data structure that is used to determine whether an element is a member of a set with a much higher space and time efficiency than other general algorithms. The results obtained using a Bloom filter may yield false positive matches, but cannot yield false negative matches. Elements can be added to the set, but cannot be removed; the more elements added to the set, the greater the likelihood of false positives.
Read more → - 295Oct 9, 20181 minmarketing
What are CAC, LTV, PBP in marketing?
Customer Acquisition Cost is the cost to convert a customer to buy a product/service. Lifetime Value is the estimated net profit we can make from a customer. Payback Period refers to the period of time required to recoup the funds expended in an investment.
Read more → - 296Oct 7, 20181 minstrategy
Mark Sellers: Technology Is Not an Economic Moat
An economic moat refers to a company's ability to maintain a competitive advantage over its rivals, protecting long-term profits and market share. Elements that do not constitute an economic moat include: technology; extensive reading; master's degrees or other degrees from top universities; experience. Elements that constitute an economic moat include: economies of scale and scope; network effects; intellectual property; high customer switching costs.
Read more → - 297Oct 3, 20181 minsystem design
Public API Choices
There are several tools for the public API, API gateway or Backend for Frontend gateway. GraphQL distinguishes itself from others for its features like tailing results, batching nested queries, performance tracing, and explicit caching.
Read more → - 298Oct 2, 20181 minstrategy
Mark Sellers: technology is not an investor's economic moat
An economic moat is the ability to maintain advantages over its competitors. It can provide protection for business’ long-term profits and market share. Technology is not an economic moat as it will always be duplicated.
Read more → - 299Oct 2, 20183 minsystem design
Past Work Experience Interview
How to conduct and evaluate past work experience interviews, with tips for interviewers and candidates.
Read more → - 300Oct 1, 20182 minsystem design
What can we communicate in soft skills interview?
An interview is a process for workers to find future co-workers. The candidate will be evaluated based on answers to three key questions: capability, willingness, and culture-fit. Any question above can not be answered without good communication.
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About Tian Pan
I'm Tian Pan, an engineer-founder focused on agentic engineering — building autonomous AI systems and scaling engineering teams. I write practical guides on system design, technical leadership, and shipping with AI agents. Previously an early engineer at Uber, Brex, and IoTeX.
