File in a Flash is a way for you to send files through the browser. The sender and receiver of the file need not install a client for the file transfer. There are several ways for you to send files to friends and co-workers. You can send files by email, send through IMs or using other file transfer clients such as BitTorrent clients.
What FileinAFlash does is act as a file transfer client for the sender and receiver. The sender of the file can easily select the file he/she wants to send directly from the FileinaFlash website. There is no need to install a plugin or download anything for this to work. A special download URL will be created for that user to share with the receiver of the file. Upon landing on the created URL, the receiver of the file will then be asked if he/she wishes to accept the file transfer. Once the accept button is pressed, the file transfer will begin on both sides. When the transfer is completed, the download URL cannot be accessed anymore.
This is a great way to quickly share files. I am not sure the file size limit of for the service but it seems that FileInAFlash doesn’t do any buffering. This simply means that they don’t save a copy of your file on their servers and time of the transfer will depend on the sender and receiver’s internet speed. It may not be for mass file sharing but it’s still worth a bookmark for those one time file requests from friends.