I tried reviews from Payperpost, Reviewme, Sponsoredposts - Costly and time consuming since we had to really dig into sites, but it worked well for some time.
The only problem was they were costly.
Using a cheaper service now with better results.
Article submission - didn't really work for me, after a year of submitting articles to thousands of directories, nothing changed.
Paid Directories - only a handful are good, rest are useless, anyway google has downgraded them now.
As for paid links, need to spend a lot of time searching for someone who can provide good links, many have stopped those after google came down on many sites which sell / buy links.
Social bookmarking, it's very limited but if done properly can be effective.
