Photo credit: Alejandro Mendoza R

1. Hab.la: Free service allows you to chat with your site's visitors from makor IM clients
2. DropSend: Share any file up to 1GB by typing your friend's email address
3. ShoutMix: Create shoutboxes for your site where users can post comments and talk to each other
4. Filemail: Send unlimited files up to 2GB each to anyone's email

1. Hab.la
   
   Hab.la is a free service to chat with your website's visitors using your existing instant messaging client. After you add a one-line code to your web-page, visitors will only see a minimized icon in the lower right corner of the browser that says "click to chat." When they click it, a little box will show up and they will be able to talk to you. Messages can be received in Meebo, Pidgin, Adium, iChat, or any other XMPP/Jabber client. Free to use.
   http://hab.la/





2. DropSend
   
   DropSend is a free website that anyone can use to store and share files online. With a simple registration and no software to install, you can easily upload any type of file up to 1GB and share with everyone by typing their email address. A message with the download link will be sent automatically to that person. Plus it can also be used to store your files online and carry them with you wherever you are. Free to use.
   http://www.dropsend.com/





3. ShoutMix
   
   ShoutMix is a free service that you can use to create and place shoutboxes on your blog or website. After you register, choose the box style and place it on your site, visitors will be able to post comments and use it to chat with you and other visitors at the same time. The free version allows you to have 250 posts stored in the shoutbox, up to 150 characters per post. You can see the pro version details here.
   http://www.shoutmix.com/





4. Filemail
   
   Filemail is a web-based file sharing system that you can use to send an unlimited number of files, up to 2GB each, to anyone who has an email address. With no registration needed, you can send any file just by selecting it from your PC through the Flash-based interface, set the options, such as the number of days the file will be available for, type the receiver's email, and click send. When the progress bar will finish, an email will be sent to your friend with the download link. Free.
   http://www.filemail.com/