Sample conversation:
Person 1: What did you think of the movie?
Person 2: Well, the acting was great, but the plot was terrible.
What does "well" actually add to the body of the sentence? I have never heard any sentence spoken or written whose meaning was absolutely dependent on beginning with "well".
It seems akin to an "um" or "uh", serving as a vocal void filler while the speaker collects their thoughts and puts their words together before actually speaking them.
If that's the case, why do people actually type it? People clearly have time to think about what they're going to say before posting a comment on a blog or replying to an email. Has it become a sort of accepted language anomaly much in the same way Midwesterners like to say things like "Where did you put it at?"