Players of The Elder Scrolls V: Skyrim will now be able to upload and download mods of any file size through the Steam Workshop, thanks to Valve's lifting on file size restrictions. The restrictions were previously in place to limit mods to 100MB, making it impossible for a good chunk of mods for the Bethesda Softworks-developed title to be hosted over the service.
Many modders instead hosted their files on sites like the Skyrim Nexus, as they were able to do so without worrying about file size limits.
In any case, anyone who uses the Nexus Mod Manager shouldn't have to worry about the change, as Bethesda states that the new patch will not interfere with the application that most players use to install and manage their mods for Skyrim.
Additionally, Skyrim's Creation Kit will be receiving an update to support unlimited sized mods, allowing modders to design mods without worrying about the size limitations.
Through the new system, the Skyrim launcher app will no longer download mods. Instead, all mod downloads will be handled through Steam itself, which will serve to place any downloaded mods in the right directories. The Skyrim launcher will simply update the .esm load order after the download's done.
Bethesda has not announced a date yet for the upcoming update, but it should be soon, if their post is anything to go by.