What is the Difference Between Perma.cc and the LexBlog Library

Someone asked me recently what the difference will be between the LexBlog Library and Perma.cc.

Perma.cc and the LexBlog Library are complementary. The purpose of each is to satisfy one fundamental need in legal research and legal citation. That being that a researcher can always “find and verify” a cited source.

They tackle digital preservation in opposite ways:

• Perma.cc, developed by the Harvard Law School Library Innovation Lab, and widely used and accepted, is reactive (A Snapshot): You use Perma.cc when you are writing. It allows you as an author to take a permanent picture of a webpage at the moment you decide to cite it. However, if a lawyer’s blog post is deleted or their firm deletes articles, the website is modified etc before someone saves it to Perma.cc, that legal insight is lost forever.
• The LexBlog Library is proactive (The Archive): It actively captures and preserves practitioner insights (like blog posts, articles, alerts, and whitepapers) as soon as they are published or submitted. It builds a permanent, stable library of legal thought, ensuring the knowledge is saved even if no one has cited it.

Though Perma.cc is obviously more established, I shared some obsevations.

Practicing lawyers looking to build lasting authority, critically important for AI, whether for LLMs or as part of legal research platforms, need proactive preservation.

Because Perma.cc takes a reactive snapshot when someone cites their work, their un-cited expertise remains not only vulnerable to vanishing from the web (no legacy), but also doesn’t work to establish authority for the lawyer.

The LexBlog Library builds a digital footprint automatically by capturing one’s writing the moment it is published or submitted and transforms it into permanent, citable secondary law.

This gets one’s insight into the legal research ecosystem, ensuring that future researchers and AI models can always “find and verify” one’s authority, regardless of whether an academic journal formally cites their work.

The users will likely differ as well. Law schools, law libraries, law reviews, courts, and legal scholars, with growing use by law firms, use Perma.cc.

The LexBlog Library will be open access enabling legal professionals not usually publishing to such levels to be cited by those publishing legal scholarship.

Perhaps the biggest distinction is whether the content being preserved is being vectorized, so as to turn a blog post, an article, a paragraph into a long string of numbers that captures its meaning rather than its words. This is required by legal publishers in the world of AI.