There's nothing more frustrating than not being able to access or open certain file formats on your Mac. With MacFUSE, however, you can easily access non-native file systems on your Mac.
MacFUSE started as a Linux open source project and was brought to Mac for a more extended handling of file systems. MacFUSE works as a system of plug-ins that quickly integrate new file systems. It allows you to mount files and folders, both local and external, as volumes and integrate them onto your system. This means, for example, you can access a drive via FTP in read/write mode directly from your Finder and handle files and folders as if they were on your own drive.
The content of these file systems can come from anywhere: from the local disk, from across the network, from memory, or any other combination of sources. What many users might love about MacFUSE is that it allows you to read and write onto drives that have not been formatted for Mac. For example, I have an external hard drive I used in Windows formatted in NTFS format which I couldn't write to before. However, using MacFUSE, I can read and write to the drive no problem. This does, however, involve the downloading and installation of the NTFS-3g package, which can be tricky for beginners.
Perhaps this illustrates one of the downsides of MACFuse - that it can be a bit difficult to understand and use for many users. In addition, transfer speeds can be as slow as 1MB/s, making reading and writing a bit painful at times.
Nevertheless, MacFUSE is a fantastic free tool to open up your Mac to other file systems and operating systems.