Why are the counts different when I view the article?

We update the social share counts in fixed time intervals, and cache them in our servers. It’s impractical to keep updating the social share count for the 100,000,000+ articles in our database in real-time. Essentially, it’s the same reason why Google toolbar’s Pagerank, or Moz’s Page Authority is not updated real-time.
However, we do update most article’s share counts on a weekly, and monthly basis, so the discrepancies should be low. We find that most pieces of content gets shared a lot in the first few days, and then gradually stops being shared.