Some of them are easy enough, e.g. a hotel name followed by a string of characters is almost certainly a confirmation number. I can easily identify titles of books I'm interested in reading or directions to somebody's house. It's probably not obvious to anybody else but the note "Ligadua = one-armed god from spirit world of Burotu" clearly refers to a detail in a Fijian story I'm trying to learn.
Disconnected phone numbers are always going to be undecipherable. Usually, they have to do with returning a phone call and, given the time frame, I suspect many of them had to do with freecycling various odds and ends.
I was apparently listening to some Broadway related radio show on-line, because I think "Davey Dinkle" refers to a song that isn't in but is related to the musical Urinetown. So the note above that, which reads "At the North Pole, global warming..." may also have to do with a Broadway Christmas album. On the other hand, it may not.
And some things will be forever mysterious. Some time in February I scribbled down the phrase "Thursday - Charity." I'm sure that was highly meaningful at the time. Damned if I know what it means now. Trying to figure that out is, however, far more entertaining than cleaning off my desk, which is what I was starting to do before deciding to try to decipher my random notes to myself.