Generally, publishers and consumers of journalism draw a distinction between reporting, 'just the facts' and opinion writing, often by restricting opinion columns to the editorial page and it's facing 'op-ed' (opposite the  editorials) page.
Unsigned editorials are traditionally the official opinions of the paper's editorial board, while op-ed pages may be a mixture of syndicated columns and other contributions, frequently with some attempt to balance the voices across some political or social spectrum.

The distinction between reporting and opinion can break down. In the UK, the press complaints commission states that, the press, whilst free to be partisan must distinguish clearly between comment, conjecture and fact but some commentators have suggested that there can sometimes be a blurring between opinion and fact.
Complex stories often require summarizing and interpretation of facts, especially if there is limited time or space for a story. Stories involving a great amount of interpretation are often labelled "news analysis," but still run in a papers news column's. The limited time for each story in a broadcast report rarely allows for such distinctions.

http://en.wikipedia.org/wiki/journalism