By default, all edits to a wiki are shown on Watchlists and Recent changes. Logged-in users can mark certain edits as 'minor' if they are merely fixing grammar, updating the layout of a page, or otherwise making changes that do not actually affect the 'content' or would not be of interest to other users. For example, I usually mark updates to my game histories on my own userpage as minor, because they probable bore everyone else.
It is possible to filter Special:Watchlists and Special:Recentchanges to ignore minor edits, which reduces the number of things to be viewed and allows major content changes to become more immediately noticeable. Spammers may also create user accounts and mark their unwanted edits as 'minor', however, so it is not advisable to dismiss them all the time!