Macs running Snow Leopard or Lion can read from drives formatted as NTFS, but they can’t write to such drives unless you install a third-party driver or muck about in the Terminal. Windows prefers to use NTFS (which stands for New Technology File System, though it has been around for nearly 20 years now).
Finally, Mac OS X’s Time Machine backup utility won’t work with FAT32. When formatting partitions, Windows 7’s Disk Management utility won’t let you create one that’s larger than 32GB, whereas Mac OS X Lion can create partitions as large as 2TB using its Disk Utility application. So if you work with bulky video clips, for example, adopting FAT32 may not be a good idea. FAT32 imposes a size limit of 4GB on single files.
The chief drawbacks of FAT32 involve file and partition size limitations. Though this format has some limitations, it enjoys nearly universal support from active platforms, including Mac and Windows operating systems, and many gaming and Linux OSs. Looking to share an external hard drive between a Mac and PC? The best way to do it is with a drive formatted as FAT32.