Hello Anonymous

I'm sure you will get a number of people recommending a number of paid-for tools. Having not used any of these extensively, I'm going to stay out of that debate.

However, there are a few free tools that I use that, while not perfect, do work well. Some can be more automated than others:

Google Alerts - keep it running. While it isn't great at picking up within the social networks (Twitter and Facebook especially) it is good at Blogs and Site Comments

Kurrently.com - I've just started using this to monitor brand mentions on Twitter and Facebook. It's seems to be working very well. Manual searches are free, and there's a monthly 'pay what you like' option if you want to subscribe to a feed.

Twitter Advanced Search - set up your search, use some operators ("" & minuses) to refine them as much as possible, and then look for the RSS feed next to the results.

Google Reader - use Reader to collate your feeds, and Star your comments to keep on top of the most relevant.

There are several other tools, I'm sure - Boardreader, Social Mention, How Sociable... but I found that the tools above are the ones I keep returning to.

I hope this helps.

Nathan.