====== About Rotation ======

Rotation is the practice of changing how thumbnails and descriptions appear on website pages. It's driven by CTR (click-through rate), which measures the ratio of clicks to impressions.

You can rotate thumbnails, text, or virtually any content.

The rotation system uses link analysis via the `link=` parameter. The script adds this parameter to each link that should be rotated. This approach is efficient because it avoids extra server load and keeps your site responsive—unlike external rotators. Here's how external rotators work:

  - A user clicks a link like `/rotator.php?thumb=123&url=http.....`
  - 100-300ms pass for the request to reach the server, 5-20ms to run the rotator script, then the user is redirected to either the gallery or the CJ script output.
  - Another 100-300ms for the redirect request, plus 5ms for its execution.

As you can see, the redirect process wastes the most time. Delays mean users wait longer, which hurts performance. Additionally, external rotators can lose click data if they independently manage skimming percentages and redirects.

Built-in rotation avoids these issues.

**Basic Concepts:** The script can rotate or shift thumbnails. Rotation sorts existing thumbnails by popularity, processes the template, and saves the result. Shifting sorts by popularity, removes the X least-clicked thumbnails, replaces them with new ones, and then processes and saves the template. Note that other events may occur during the shift, which are discussed in the groups section.

**CTR Calculation:** Rotation is based on the CTR principle. If a thumbnail received 5 clicks out of 100 total page clicks, its CTR is 5%.

For accuracy (since traffic quality varies hourly), the script uses total clicks on the page—not impressions—to calculate CTR. So if a page had 100 total clicks and 5 were on a specific thumbnail, that thumbnail's CTR is 5%.

Thumbnails are sorted by CTR on the home page. Some rotators, like ST and DTR, experience a "stickiness" effect where top-performing thumbnails stay at the top because their position boosts their CTR. New thumbnails struggle to dislodge them. To prevent this, we calculate CTR based only on the last X impressions.

**Gallery Statuses:** There are four statuses.

  * **Active** — Galleries currently being rotated and displayed on the page.
  * **Pool** — A reserve of galleries ready for rotation. During a shift, galleries move from Pool to Active.
  * **Old** — Galleries removed from Active during a shift. Part of Pool moves to Active; part of Active moves to Old.
  * **N/A** — The script couldn't reach this gallery during a check. It's temporarily inactive and will return to its normal status later.