Betelgeuse asked a great question in another thread:
"How did the (AC/DC) LE have separate ratings before now if the Premium/LE were lumped together as one game?"
Answer:
I use SQL to look for patterns in the review text such as "LE", "Limited", "LTBR", "BIBLE", " Let there be rock", "back in black" (not case sensitive) and text not like "prem" or "luci". Then I skim through those results to see if there are any false positives ie ("I like Deadpool LE better than this game").
There's always a couple of reviews that are small novels that might be categorized incorrectly but I'd say the process is 95% accurate.
The ads are a little easier as there is both a title and description to analyze, but you still get descriptions like "I'm selling this game in order to get a LE", so I have to read through them as well to eliminate false positives.
That being said - if anyone sees an ad or review that's improperly linked, shoot me a PM and I'll get it corrected.