What is Flv ?

SWF is not the only Flash format. FLV files (Flash Video Files) are a binary file format that delivers "bitmapped" video, limited to one video and one audio stream per file, over the Internet to the Macromedia Flash Player version 7. FLV content may also be associated with SWF files by ActionScript external references. FLV format can also imported into Macromedia Flash Authoring tool. Unlike SWF format, FLV do not have maximum of 16000 Topframes limitation and ideally for large video file size.

The format has quickly established itself as the format of choice for embedded video on the web. Notable users of the Flash Video format include YouTube, Google Video, Yahoo! Video, metacafe, Reuters.com, and many other news providers. The standards documentation for BBC Online deprecates the use of other formats previously in use on its sites[3] such as RealVideo or WMV.

How to play .FLV files on Mac (Snow Leopard included)?

In order to play FLV (Flash Video) files on your Mac, you need FLV players. Here are two recommendations (both of them are FREE):

1. VLC Media Player
The VLC Media Player is a free, cross-platform media player that supports a large number of multimedia formats, without the need for additional codes. It can handle FLV, WMV and VOB files to name a few.

2. Perian
Perian is a free, open source QuickTime component that adds native support for many popular media formats including FLV, MKV, AVI, DivX, 3ivX, FLV1, FSV1, Flash ADPCM and many more.

How to download flash videos from video sites on Mac for free?

You can download the flash video (.FLV files, the default video format that most video social sites are using) from online video host into your local hard disk. With some tricks, it's now very easy to download the videos hosted and shared on online video sites such as YouTube and Google Video. You can follow this guides: http://www.moviesmac.com/tutorial/download-youtube-on-mac.html