I used to have some complex set-up that worked intermittently. Now however, I’ve started using TwitterFeed which is much simpler to manage and seems pretty robust.
To make things slightly more complex, I also feed a summary of my Diigo links to my Blog on a daily basis using the tools on the Diigo web site. So I filter these entries out of TwitterFeed using their filtering facility.
Sounds complex but it is pretty straight-forwards to set up and it then just works.