Tekkit rose to prominence as a mod-pack orientated for SMP users created by users from SomethingAwful; this was an important distinction, as before the release of Minecraft 1.3.2, a Minecraft Mod had to be specifically coded as either SSP (Survival Single Player) or SMP (Survival MultiPlayer).
Due to the changes in Minecraft 1.3.2, Technic was discontinued, and Tekkit was split in two; Tekkit Classic, which uses Minecraft 1.2.5 as a base, and Tekkit Lite, which has been updated for Minecraft 1.4.7.