FrostWire performs a smart search upon the most relevant torrent search results that come from BitTorrent search engines, meaning it remembers every file contained by every torrent it scans, increasing greatly the odds of finding what you are looking for, super-fast.
As FrostWire fetches search results from the search engines, it uses these results to crawl the Azureus DHT to learn about the contents indexed by these torrents. FrostWire will not use the bandwidth of the search engines in this process; it will only use the torrent info hash to perform DHT queries, meaning .torrent files are fetched only from the DHT, not from the search engines' Web servers. Its search power will not depend upon a central entity.
FrostWire is also capable of downloading directly from cloud sources [Soundcloud], has a full file library and file player built in. There's also an Android app that can transfer files easily [on Wi-Fi] between their Macs and their phones using the FrostWire application.
Note: While the software is classified as freeware, it is actually donationware. Please consider making a donation to help support development.