Social bookmarking and search engine submission has worked well for me.Also try niche related forums with signatures.
I agree with mkr30: Word of mouth = viral = another facebook The question is a bit if a piece of string question to be honest: best, well if budget is not an object then anything. i give a million pounds to an advertising agency and they get me hits down to what site and serps.
You already have a lot of good answears to Your question. Just try some of the recommended methods and see which one brings You better results and which one You feel more confortable with. Then keep working on those!
The Only Traffic-Generating Strategies I Use If you are serious try this: 1; Distributing "Viral" eBooks and "mutually-beneficial." 2; "mutually-beneficial." Find marketers and business owners who already have large "responsive" mailing lists and make them an offer they can't refuse! Your offer has to benefit them as well - in a big way.
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