In other words, if 80% of a game's players left a favorable review, eight out of its top ten reviews will be positive. That will help keep the small amount of artificially-inflated 'bombed' posts from drowning out feedback that's representative of the community's opinion.
The other fix tracks how many times an account votes that reviews are 'helpful' for a single game. Most users just mark a few reviews as helpful or not, and that feedback will continue to be counted normally. Those that blatantly mass-downvote other reviews -- typically around 10,000 times on a single game, the Steam blog noted -- will see each additional vote diluted more and more.
It's continual tinkering that reflects how difficult it is to provide democratic and current feedback for a game to prospective buyers. Recently, Steam implemented a change that heavily weighted recent reviews to reflect the current state of the game and highlighted those with the highest percentage of 'helpful' votes; This unintentionally enabled 'review bombing.'
This won't be the last fix coming to Steam's review system, either: Future tweaks will address how players feel about a game now after updates and changes, as well as filtering to account for issues that only affect players in certain regions.