I have been using this cool technique for a while now.  It drives quality targeted traffic to your blog/site for FREE.  What it basically does it send you alerts as blogs are updated so that you can be the first to comment.  (The first comment usually gets their link clicked the most times!)

Read and follow the following steps:
1. Set up an account in Google Alert
2. Choose your niche keywords
3. Set your alert types as “comprehensive” and “as it happens”
4. When you receive an alert, use it to post your comment on that blog post (with your link of course).

(If you are going to use MANY alerts, perhaps you should consider opening a dedicated Google email…)

Everyone should be doing this. Setup your Gmail email filters so they automatically get labeled appropriately as they come.

If you really want to scale this, you might consider hiring an offshore company to do this for you.  Have them post comments to all articles that come in through the Google Alerts filter that you set up.