Several other Mac compression utilities appeared and disappeared during the 1990s, but none became a real threat to StuffIt's dominance. The only ones to see any widespread use were special-purpose "disk expanders" like DiskDoubler and SuperDisk!, which served a different niche. Apparently as a side-effect, StuffIt once again saw few upgrades. The file format changed in a number of major revisions, leading to incompatible updates. PC-based formats long surpassed the original StuffIt format in terms of compression, notably newer systems like RAR and 7z. These had little impact on the Mac market, as most of these never appeared in an easy-to-use program on the Mac.