This category is sort of a broad-topic classification for parties and party-like organizations which promote "socialism." Since both communists and democratic socialists use the term "socialism" to describe their ideologies, even though they are vastly different in some respects, they are both in this category.
Social democratic/democratic socialist parties and organizations are lumped into the "democratic socialist" subcat. Here you will find organizations such as the Socialist Party and the Democratic Socialists of America.
Communist or radical Marxist/vanguardist groups are placed in "Communist-Marxist." Within this category are subcats for derived ideologies of DeLeonism, Stalinism, Maoism, and Trotskyism.
Groups which defy easy categorization by being vague in their stances or by sharing elements of social democracy and communism are placed in the top level of the category.
The "Youth Groups" subcat contains various socialist/communist youth groups, some of which are affiliates of larger parties which are listed in their respective subcats.
The "State Chapters" category contains localized socialist/communist groups, as well as state/local chapters of the Communist Party and Socialist Party.
The @links are for other political affiliations often related to Democratic Socialists. "Libertarian Socialism," a.k.a. Anarchism, generally adheres to the same ideals as socialism, but includes advocating the eventual dissolution of government. "Greens" are a fast-growing eco-political movement which often has social and environmental stances on par with social democratic groups. The "New Party" link is to the relatively new "New Party" which is a progressive party with many stances similar to those of Democratic Socialist organizations.
This category contains category links to state-level Socialist(s) categories and category links to State and Local categories of individual Democratic Socialist and Marxist socialist party categories, such as Socialist Party, USA or the Community Party.