---
title: "Blog | Ceisium"
description: "Ceisium Blog notes on website search, crawl quality, relevance, and keeping public product content easy to find as your site changes."
canonical: https://ceisium.com/blog/
---

> For the complete documentation and public content index, see [llms.txt](/llms.txt). This page is the Markdown alternative to the canonical HTML page.

# Index

[All](https://ceisium.com/blog/) [Learn](https://ceisium.com/blog/?tag=Learn) [Search](https://ceisium.com/blog/?tag=Search)

## Recent articles

[

![Five documentation cards pass through Boolean set paths and become three search candidates.](https://ceisium.com/blog/boolean-retrieval-cover.webp)

### Boolean Retrieval: AND, OR, and NOT in Search

Learn how Boolean search uses AND, OR, and NOT to combine result sets, where exact control helps, and why website search still needs ranking.

Yuvraj · Jul 21, 2026

](https://ceisium.com/blog/boolean-retrieval/)

[

![Equal query-term matches sit in short and long document lanes against one average-length reference.](https://ceisium.com/blog/document-length-normalization-cover.webp)

### Document Length Normalization: Why Long Pages Need Context

Learn why long pages get more chances to match a search query, how BM25 adjusts for relative document length, and why shorter is not automatically better.

Yuvraj · Jul 21, 2026

](https://ceisium.com/blog/document-length-normalization/)

[

![Website routes pass through crawl boundaries into a search corpus before a query selects candidates.](https://ceisium.com/blog/website-crawling-search-quality-cover.webp)

### How Website Crawling Shapes Search Quality

Learn how crawl scope, sitemaps, rendering, URL identity, and recrawl freshness shape the pages a site-search ranker can choose from.

Yuvraj · Jul 21, 2026

](https://ceisium.com/blog/how-website-crawling-shapes-search-quality/)

[

![A query splits into a precise token path and a semantic neighborhood, then becomes one ranked shortlist.](https://ceisium.com/blog/semantic-search-vs-keyword-search-cover.webp)

### Semantic Search vs Keyword Search: How to Choose and When to Combine Them

Keyword search uses literal evidence. Embedding-based semantic search bridges vocabulary gaps. Learn where each fails and when hybrid retrieval earns its added complexity.

Yuvraj · Jul 21, 2026

](https://ceisium.com/blog/semantic-search-vs-keyword-search/)

[

![Keyword and vector result paths join to make one ordered hybrid search result list.](https://ceisium.com/blog/hybrid-search-cover-ceisium.webp)

### What Is Hybrid Search?

Hybrid search combines keyword and vector retrieval. Learn how fusion, candidate windows, filters, and reranking turn two result lists into one.

Yuvraj · Jul 21, 2026

](https://ceisium.com/blog/what-is-hybrid-search/)

[

![A continuous text signal passes through boundary planes and becomes separate token blocks.](https://ceisium.com/blog/tokenization-cover.webp)

### What Is Tokenization in Search?

Learn how search engines split and normalize page text and queries into searchable terms, and why those choices can decide which pages reach ranking.

Yuvraj · Jul 21, 2026

](https://ceisium.com/blog/what-is-tokenization-in-search/)

## Previous Posts

[BM25 in RAG: Why Exact Keywords Still Matter Yuvraj · Jul 15, 2026](https://ceisium.com/blog/bm25-in-rag/) [What Is an Inverted Index? Yuvraj · Jul 15, 2026](https://ceisium.com/blog/what-is-an-inverted-index/) [What Is Vector Search? Yuvraj · Jul 10, 2026](https://ceisium.com/blog/what-is-vector-search/) [What is Inverse Document Frequency? Yuvraj · Jul 02, 2026](https://ceisium.com/blog/what-is-inverse-document-frequency/) [TF-IDF: The Search Ranking Idea Behind BM25 Yuvraj · Jul 01, 2026](https://ceisium.com/blog/what-is-tf-idf/) [What is BM25? A Plain English Guide Yuvraj · Jun 24, 2026](https://ceisium.com/blog/what-is-bm25/)