If you are a Safari user then you might be familiar with the program's Bookmarks bar, where you can save links to individual Web pages, or group them as collections in folders.
You can also use it to save any other location you can link to through Safari's address bar, including files and folders on the system.
To do this, simply drag a file to the address bar, and you should see a bookmark to it as you would any other file. You can also load some files such as images directly into Safari by dropping them on a Safari window, and then bookmark them as you would any Web URL.
This feature might be useful for quick-linking to files you commonly access, such as a text document of recipes, quotes, signatures, or other details you might use when browsing the Web, posting on forums and social media sites, or otherwise.
You can even add folders to the Bookmarks bar, but you can only do so indirectly by adding a file, and then editing the bookmark link and removing the file so only the desired path is present. Depending on your Safari version, doing this may reveal the folder in the Finder, or may show you a hierarchical drop-down menu of the folder's contents.
While useful, this feature does have limitations. Since you cannot drag folders directly to the Bookmarks bar, files that are packaged, such as Pages documents, cannot be dragged to the bar. It will only work with formats that are saved in a single file.
Beyond file and folder access, you can edit the links to point to FTP, AFP, and SMB servers and the shares in them, or even to VNC servers to quickly invoke screen sharing. You can organize these bookmarks into folders, and be able to access shared computers directly from within Safari.
As with file access, using these links will open the default program that handles them (e.g., Screen Sharing for VNC connections), so while Safari will open JPEG and PDF files in the browser window, it will not do so for TXT and RTF files, and instead open these in TextEdit or whatever default handler you have set for these formats.