/* synchronize access on {@link #newSones}. */
private Set<String> knownSones = new HashSet<String>();
/* synchronize access on {@link #newSones}. */
private Set<String> knownSones = new HashSet<String>();
/* synchronize access on {@link #newPosts}. */
private Set<String> knownPosts = new HashSet<String>();
/* synchronize access on {@link #newPosts}. */
private Set<String> knownPosts = new HashSet<String>();