Open source social media monitoring tools for agencies?

Are there any free or open source social media monitoring tools for a small agency? We just started the business so want to go with any free alternatives out there to bootstrap.

Sure, there are lots, though they vary in quality.

• Google Alerts - Perhaps one of the best ones out there for blogs, news articles, and other websites.
• Google Trends - This product is often overlooked, and perhaps not as valuable for small brands, but can yield interesting results.
• Wildfire - Compares social media mentions between multiple accounts on various services.
• TweetDeck - Create a set of columns that search for particular keywords or monitors lists.
• HootSuite - Or create a set of columns here for keywords across various social media services.

Here are a set of services with free plans that monitor social media sites. I personally don't use any of these regularly, but for the price, it may be worthwhile just to check them out.

• Howsociable
• SocialMention
• Addict-o-matic
• Omgili - searches forums

Finally, many social media services have a unique URL for search results (in dev terms, the search term usually appears in the querystring). You can bookmark these URLs for a list of handy URLs to track. Here are examples using "kindle" as the search term.

• Twitter
• Google+
• Tumblr
• Pinterest
• Reddit
• YouTube
• Digg
• Quora
• etc

With all of those direct URLs to search results, it wouldn't be too difficult for someone technically-inclined to whip up a down & dirty social media monitoring service. And with that in mind, here are some open source social media monitoring repos from GitHub. I haven't tried any of them, so I can't speak to their effectiveness.

• GitHub social media monitoring repos