May I suggest that anyone looking to hone in on conversations, curate content and/or topic-tag for reach needs to use the brand new social media tool, for brand monitoring, listening, topic smart-tagging, and content curation (with proper referencing of original content creators): RiteTag is a tool for finding the "rite" tags for many social networks based on your query. We also provide stats and examples of recent updates with each tag suggested, so people can learn about the types of content that tends to go with a tag.
Some tools do tag illustration. Also, they do the job just with Twitter; RiteTag.com already has 10 social neworks (with topic-tagging) integrated, and will expand to more than 20 - which people can search on simultaneously. RiteTag - to find the rite tags, per network (they vary per network) and learn about tags as well. Its not about SEO, but SSO: social sharing optimization: optimizing social media updates to be seen by those not following you by name, but following and searching for your tagged topics. And absolutely nothing out there does what RiteTag.com does for this, not for one network, let alone the ten that we already have integrated.