Hi Cameron,
When struggling over Twitter, +Google or any other social network, I would firstly ask my self if the content of the website is really engaging? Is it really worth sharing it?
If the answer is yes, you most then probably are missing the call to action over the website (just name it and your visitors will follow).
Point out if the article was useful share it with their friends, get something unique over the social networks, make worth it to follow you over there (they get the information faster, there is a community in the background, etc)
As for twiends.com, I've never used it, but it doesn't sound bad (if you list yourself in the right place), but don't forget to place quality before quantity.
I hope this helped gain another view of the problem (even If I couldn't directly help with Twiends.com).
Istvan