If you suddenly see little red exclamation marks (!) on recent changes, that means your account is now old enough to allow you patrolling.
Patrolling is basically user-based content control. In many cases, you check out edits that aren't your own, simply to see what was added, and to fix mistakes made. But what if the edit is fine? You do nothing. And what does the next one coming along do? Check out the edit as well, because he doesn't know you checked it already!
That is where patrolling comes into play.
Red exclamation marks highlight all edits that have not been marked as checked yet. If you see such an edit, click on the "diff" link next to it. This will show you the difference between the edit before, and the edit that was done. If the edit is spam or vandalism, revert as usual and warn or tag the user as usual. But if it is okay, click the fancy new [Mark as patrolled] link you have now (below the revision info/summary on the right side). That will mark the edit as patrolled (hence the name) and remove the red exclamation mark on recent changes. That way, other users know this edit has been investigated and is a valid contribution to LGPedia, and don't have to spam-check it on their own. (In order to patrol a new page, go to the page, and locate the [Mark this article as patrolled] link at the bottom of the page.)
If you do find a spam revision, but don't know how to revert, or don't have the time, simply don't mark it as patrolled - that will leave the edit marked as unpatrolled and people will keep looking at it until someone who knows how to revert it finally does.
Do not, under any circumstances, mark spam or vandalized edits as patrolled. That defeats the purpose of the system.