Hello!
I do manage and update them all myself. I had my site built by a good friend of mine but then I maintain it (clearly not as often as I should, a project for this weekend in fact). It is a lot of work to hit all the pertinent social networks, but everyone has their own system of how they do it and once you get into a stride with it it gets easier.
If you’re starting out Id start with tumblr. The community nature of tumblr helps you network and get your work out there. I can 100% say I got back into photography because of tumblr and the community I found here. In my opinion a site is totally just to legitimize yourself for professional contacts.
Id recommend starting a tumblr, and posting just your own work. It gets confusing, sometimes, when you’re starting if you’re reblogging 20 shots a day and posting 1. Network with other photographers and models through tumblr, flickr, instagram and build you connections that way. That is how I did it.
Best of luck!
Derek