Let's take a simple example of how you can have a bunch of pages with little content. I've simplified this and lets say both posts where done in the same month/year but on two different days.
Home page: Counts as 1 page to SE
Post 1: 2 categories and 4 tags: Counts as 7 pages to SE (1post + 2 categories pages + 4 tags pages = 7 pages)
Post 2: two different categories, 4 different tags: (Again 7 pages to a SE)
About page: counts as 1 page to SE
Archives page displaying year: 2 posts listed on one page (1 page to a SE)
Archives post displaying month 2 posts listed on one page (1 page to a SE)
Archives page displaying days (1 post each on two different day archive pages (2 pages to a SE)
Total pages for 2 posts made on 2 different days in the same month/year, a home page and an about page = 20 pages total to a SE.