Spam comes in a variety of ways, and how it is delivered constantly changes. Marking comments, entries, and messages as spam instead of just deleting them helps LiveJournal to identify and remove spammers. You can control your exposure to spam, and deal with any spam you receive, by taking the following steps.
Any user can read the already published content, post new entries in his journal, upload photos and videos. However, depending on a number of factors, you may have more opportunities.