I have had a Smugmug site -
www.jhluxton.com since 2010, though I have only really started to seriously develop it in the past 18 months.
For many years - almost since the world wide web started in the 1990s I ran a conventional web site which was edited using various versions of Microsoft Front Page. This site focused on just one area of transport - shipping.
As time went on the site became too large and when Microsoft ceased supporting Front Page I found it far too large to convert to an alternative format.
By then I had been playing around with SmugMug - but had not put much effort into it. With the old site taken off line just over a year ago I have been able to spend more time on the SmugMug site.
In terms of cost SmugMug costs around the same as what I was paying for a pro hosting package with 1&1 Internet on which I had run my old web site irishseashipping.com .
The one disadvantage I can see with SmugMug and I always remain aware of is that unlike my old web site all the structure is hosted remotely not on your own pc - whilst I obviously have the picture files any other work would cease to exist if SmugMug were to shut up shop and it would be completely back to the drawing board.
However, SmugMug does appear well established now, and perhaps these concerns are no longer that great - it is now customisable for the UK market that wasn't the case when I first joined and everthing was in US$. However, you should be aware that the subscription is payable in US$ and will fluctuate depending on the exchange rate.
As for selling images - yes I have sold a few - but the amount held by Smugmug has not yet reached £50 thus I have never claimed it. I run the site as I enjoy sharing my images and have a massive and ever growing collection of digital images and over 16,000 transparencies some dating from my teens in the 1970s. I find Smugmug quite flexible now that I have got the hang of it.
Money making isn't the main point its allowing others to see your pictures I think, though the chance of making a few pounds is an incentive.
In the next few years I hope to develop the site even further now that I have decided to start winding down from my job and only work part time.
Some of the time freed up will be used to increase the number and variety of images hosted on SmugMug as I feel that the more you have on line the more likely you will have a photograph that someone wants.
If I were you I would give SmugMug a try - but do not expect to become rich of even cover your costs.
What you also need to do is drive traffic to a SmugMug site - I post samples with links to various forums etc I am a member of, and also use Flickr to promote new updates again with one or two samples for each updated with a click here link from the Flickr description which lead to the Smugmug pages.
I am not a great fan of social networking and I am not an active user of Facebook - but that could also be used to promote updates.
Hope this info is of use
John