I'm very new to social bookmarking websites but I know that many people use them and search engines like them and rank websites higher. I'm starting a campaign and hiring somebody to do some posts on them. Do I need to keep posting periodically (if yet, how often) or I can just post once and move on.
There are many social bookmarking websites available on the net and once you submitted your site url you can move to the other social bookmarking websites.If there are many webpages available on the site then submit that also to social bookmarking websites.
Unfortunately, social bookmarking doesn't carry the weight that it once did. This doesn't mean that it's not effective, you just have to make sure that you are using other efforts as well.
This is an excellent list (not mine) of follow social book marking sites with page ranks http://www.freeways-to-make-money-online.com/?p=9
I recommend that you keep bookmarking every new page that you create, choose let's say.. 20 social bookmarks and alweays bookmark a new page with 20 of them
onlywire is great, but if you got the cash I recoment bookmarking demon. Let you bookmark to thousends of bookmarking and pligg sites. Takes some time to set up, but when you are good to go, it's golden! 180$ is abit much thouge.
social bookmarking helps your site to be indexed sooner. But driving traffic depends upon your content & reputation. Hiring people should be based upon track-records.