On wogma, each film has 4 types of ratings: a wogma rating, wogma user ratings, external review rating, and twitter rating. Sometimes there will be huge difference in the ratings across these. Though it is difficult to figure out exactly why this happens, my inference is that since the external reviews comprises of reviewers who most-likely watch all films, they don't pick what they see, they see ALL films. On the other hand, twitter ratings are from people who have gone to see a film out of choice.
Another reason could be that an external reviewer on an average must watch more films than a twitterer (who's films are rated). This might make the external reviewer more critical of a certian type of film and more appreciative of a 'different' film.
These are just my inferences. Here are some of the details of how these reviews/twitter ratings are calculated.
The external reviews section lists the rating and excerpt of regular reviewers. I go through about 75 sites for every film and judge the rating from a cursory glance on the review and the star rating if there is one on the day I go through the sites (usually a Monday).
Regular reviewers are those sites/blogs that have had at least 3 hindi films reviewed in the last 3 months. I try my best to not include these reviews in the twitter ratings.
If you see any errors, please let me know. If you know of a site that falls in these criteria, and is not seen here, do drop an e-mail.
For each film with a twitter rating, I go through tweets mentioning the name of the film (and spelling variations, I could think of.) I try my best to filter out spammers, repeat tweets by same twitter-id, re-tweets, etc. I also filter out tweets that are already in the external reviews section. I create a ranking based on the tweets.
If you see an error do let me know.