Last week, we presented part one of the 20 most useful new social media tools of 2011, which featured Nos. 20 to 16 on the list.

Now, it’s time for part two—our picks for Nos. 15 to 11.

Here we go: The 20 most useful new social media tools of 2011, part two:

15. Unilyzer.com. If you’re responsible for measuring the performance of your social media channels, this is the analytics hub for you. Simply plug in all of your details—Twitter account, YouTube channel, Google analytics, etc.—and Unilyzer will show all of your data on one screen. Check out the full list of product features here.

14. Quixey.com. This is a search engine for apps (Android, Mac, Chrome, Facebook, Web, and more), which takes away the pain from those endless searches for apps via general search engines. Bookmark this one!

13. GroupHigh.com. If you haven’t tried GroupHigh yet, the next sentence might encourage you to do so. GroupHigh.com is the best blogger outreach research and engagement tool on the planet. The latest update (version three) makes it even easier for you to discover the most relevant blogs by keyword, style, and receptiveness. Brilliant.

12. PeopleBrowsr.com/Kred.ly. PeopleBrowsr is a social media analytics tool that includes 1,000 days of Twitter data at your disposal. Kred, from the same team, is an influence measurement tool that provides a transparent analysis of user activity. Combined, these tools can make your life much easier.

11. Knowem.com. This is primarily a social media username-checking tool, but it is also a great place to start when identifying online communities relevant to a subject or topic. Simply visit the networks tab and scroll through the categories to discover new places to be active and/or monitor.

Don’t miss the next installment, when we unveil Nos. 10 to 6.

On the Paratus Communications blog, PR Daily Europe contributing editor Adam Vincenzini rounds up five of the most-talked-about social media platforms each week. The feature is called Platform Five. Adam has agreed to simulcast it on PR Daily. If you’d like to check out the previous editions, they’re all here for you to browse through.