also, creating a paid (or unpaid if you can) affiliate structure / widget / linking relationship with other bloggers can lead to continuing, long-term traffic drivers for user acquisition (assuming you know your economics). especially if the bloggers in question are content-specific & aligned with your audience, could be a great way to drive relevant, monetizable traffic. whether it’s in enough volume to make a difference is probably specific to your business.

lastly, SEM can work very well as a regular traffic driver if 1) the volume of available search traffic is large (enough), and 2) your customer acquisition cost can be arbitraged based on a higher customer value created on your site. i wouldn’t recommend this for most web 2.0 startups with low per-user value and/or fuzzy biz models, but could work well for defined, targeted category verticals with well-understood economics.

all things being equal tho, i agree that regular, organic free traffic is better than one-time, paid traffic.

Here is a little known secret: if one does continual, informational and factual press releases, that these releases, for some, can get find there way into traditional media news feed circuits. It is a great exercise for linkbuilding and improving SEO rankings if one can ensure that the information released is both newsorthy and press worthy.

As the internet continues to become more pervasive, sites that establish themselves as thought leaders can use traditional, social media and viral channels to drive traffic via the use of original content.

Your point about PR being less effective for user acquisition holds though. It can however be incredibly effective to raise your profile among potential employees, partners, investors and acquirers. You just need to know what your objective is and match your PR strategy to suit. More at

http://lsvp.wordpress.com/2007/10/15/seven-things-entrepreneurs-should-know-about-pr/