'Sup! Not gonna write too much in here, I'm just going to give a quick guide on my rating system, as to avoid any misunderstandings in case you decide to check it out:
Top tier - My taste > Your taste.
10 - FUKKEN MASTERPIECE... basically reserved for my favourite series. Favorite'ing it is just not enough (LOVE E7!).
9 - Series/Movies that I'd recommend on the spot. Usually the best of their respective genres and demographics (Be it mecha, slice of life, drama, sports, shonen, seinen, shojo, josei, etc etc). Unless you have a special dislike/hate for that type of shows, chances are that it'll be liked.
8 - Series/Movies that I'd usually recommend, giving a little thought to what the person in question is interested in. Not necessarily top tier, but very good stuff.
7 - Series/Movies that I'd recommend if specifically searching for stuff of a particular genre or demographic and has seen all of the 8+ stuff. Decent stuff with interesting aspects.
6 - Series/Movies that I'd usually not recommend unless for something specific. Usually mediocre but with some redeeming value or interesting point.
Bottom Tier - Also known as the "Why the fuck did I watch this?" tier. Chances are that if it's a long series, I dropped it at the first few episodes and/or deleted it, thus just not being in the list or rated. So mostly bad OVAs or Movies.
5 - Series/Movies that were mediocre/below and with little to no interesting aspects. Wouldn't recommend. Not necessarily HORRIBLE, just not good... or decent.
4 - Things that I would recommend... NOT watching.
3 - Watch for shit and giggles... WHAT ARE YOU DOING WITH YOUR LIFE?
2 - Why the hell did you download this? Erase, empty the recycle bin and wash your eyes.
1 - Mars of Destruction.
If it has no rating and is in the completed section, chances are that it's a small OVA that depends on a longer series, or something of the sort.
For on-hold, dropped or watching, no rating. I have to complete something to rate... thus, BAD... [EVIL] long stuff won't usually be rated. I don't 'drop' that much any way, I either completely delete it from MAL (or just never add it), don't get anywhere near it in the first place or slips to the on-hold section, where it'll be 'till the end of time (not everything in the On-hold is bad though, some, or hell, most, are there because I'm a lazy jerk).
Mostly to use with the Anime List, as my Manga List is a mess and I don't feel like completing and ordering it.