1-3: Non-threatening stalker. Might be creepy but not always. Unlikely to force a meeting or conversation between themself and the stalkee.
4-6: Has the potential to seek the stalkee out, but won't for certain. The middle ground on the stalker level, for those stalkers whose motives you aren't sure of.
7-9: Creepy stalker. Will go out of his or her way to try and meet or converse with the stalkee. Never knowingly go to a place you may encounter a 7-9 level stalker by yourself.
10: File the restraining order.