Saving, re-reading, browsing, searching, and organizing your lore all of these are easier with computer-based tools. You *can* keep lore without computers, but it is harder think of what Leonardo da Vinci must have gone through each time he wanted to look up something in his notebooks.
In the early days of the Internet, often the cheapest way to manage your lore was to craft the tools yourself. This was the approach I took with the TCE Corporate Technical Memory, an early 1990s-era Web-based knowledge management system written in Perl and Oracle. The only alternative platform at that point in time suitable for deploying the Corporate Technical Memory was Lotus Notes, which would have cost the equivalent of several years of my salary to deploy fully (for what was very nearly a skunkworks project).
Life (and software engineering) is different here in the 21st century and I'm not just talking about the shiny silver spacesuits we wear all the time, either
Wikis are a software system well-suited to lore-keeping, as wikis make it easy to store, organize, search, and retrieve relatively unstructured text. One such wiki is Kwiki, about which I've already blogged on how easy it is to create a Corporate Technical Memory clone. With Kwiki and its plug-ins, you can have every feature that was implemented in the Corporate Technical Memory *and* every feature planned for the Corporate Technical Memory except for an Authority Section (an Authority Section marks some pages as authoritative). Kwiki has plug-ins for searching, user authentication, source control, tagging, file upload, and RSS feed generation, along with a host of other capabilities.
A couple of other classes of software that could be used for lore-keeping are mindmappers and free-text databases. I confess that I have not ever used these classes of software for lore-keeping, so I don't know how well they perform in real life. Mindmapping software would give you a way to organize all your lore by how the lore maps to categories, where you set up the categories. Free-text databases are notable for allowing many different ways to tag, search, and browse your text, which is helpful in lore-keeping. I know there are Open Source tools for mindmapping. I suspect there are Open Source free-text databases, but I don't know what they are.