Exposure is key Karen - the more people who see your work, the more chance you'll get recognition. Having said that, I'm not keen on posting on every site - just a select few...
www.1x.com for example, I have no images in the gallery (a long convaluted procedure where you have to have your images critiqued before they go public - but you need to critique 3 others before yours can be critiqued) - but I have made a sale out of it! Found a publisher in the forum (not a million miles from PR's publisher

) - sent a link to my website and a few months later we're in print with cash in the bank

I've also tried
www.myshutterspace.com but didn't really get much out of it - lots of 'awesome' type comments...
Thanks for the link Jim. Initial look seems interesting - will have a proper delve later.
Cheers
Andy