It does work, but social bookmarking isn't nearly the panacea that it was a year or two ago. That being said Onlywire does an excellent job (especially for the price, free) of submitting links to such a large number of sites.
Major improvements and changes have been made to OnlyWire. It works great now. Many other new improvements are also in the works.
I signed up, but its not good, manual is much better. I just have a folder ready and then click on the bookmarks I want.
Interesting thread. I was just taking a look at their service yesterday. I used them about 2 years ago but I guess a lot has changed since then. Besides onlywire, I guess there are lot more other options for you to explore and perhaps a bit cheaper too.
Onlywire used to be free. Currently they are charging too high for a simple services. The charges are not 1 time fee, but monthly. Totally not worth it. You can use socialmarker or socialposter for the same results, though have to do semi-manually.
Sometimes you will get some failed delivery, but not all. You can resend it. Overall, I think OnlyWire is one of the best service that you can use for free.