Photo sites

[aropilot]

As a next step in my journey in photography, I notice many folks have flikr accounts or some other "place" to post their work. I think I'm ready to begin posting my work as well, as I've had a few opportunities to freelance for friends to get me started.
In a brief way can some of you please give me an overview of how this works? I have a website for my business to showcase what we do, pre-and-post project pics of our work etc. so I imagine this works the same way in general terms for photography but I'm also looking for reasons one would choose a specific "place": advantages, ease, exposure to the public, etc.
Okay, it's a bit more than I initially intended but, we are all here to learn so, THANKS !!

[OsmosisStudios]

Many use Flickr because it's large and fairly easy to use. I dont, but only because I found it to be overwhelming. I instead use deviantArt. Smaller community, but a bit more connected.

[nicotine]

I use deviantART and http://picmember.com. deviantART is for the community and Picmember is my general picture host.