Account Registration & Login
For member registration, we store your email address, authentication method, and member identifier. Google sign-in uses an identifier issued by Google and your verified email address. We do not collect your name, address, or telephone number, and we do not use passwords. Access to Google is limited to what is required for sign-in.
Email verification codes are sent to the specified address to verify your identity and expire after 10 minutes. Expired code-verification data and data used to limit sending and attempts are deleted during authentication. An authentication cookie keeps you signed in. Analytics-service scripts are not loaded on member pages.
View-feature usage is counted by member. To prevent excessive use of authentication and maps, we also use a keyed one-way transformation of the originating IP address. Per-member and per-source map usage records are deleted after about seven days. Favorites and analyses you explicitly save are visible only to you and can be deleted from My Page.
Favorite-update emails are sent only when you enable them. We store the selected verified email address, subscription setting and its date and time, and the update identifier, send date, and delivery result needed to prevent duplicate messages. You can stop them at any time from the favorite-updates page. Previous delivery records are retained after you unsubscribe to prevent duplicates and investigate failures.
To understand service usage, we count member registrations and signed-in page views and visits on our own server. Visit records contain only a keyed one-way transformation of the member ID and the view time; they do not include email addresses, detailed URLs, entered content, or IP addresses. Visit records are retained for 400 days. No external analytics scripts are added to member pages.
To understand which prompt led to registration, at the time of a new registration we select one type of sign-up prompt most recently clicked in the same browser, such as a home-page banner or members-only prompt, and record only the registration date and prompt type. This record contains no member identifier, anonymous browser identifier, or time, and is not linked to member information or browsing records. It is retained for 400 days.
Data Recorded by Analytics
We record the page path, views, scrolling, time spent, link and button interactions, screen version, active display experiments, and browser language settings (e.g. ja or en-US). For visits from external promotions, we also record source, medium, and campaign identifiers attached to the URL. For search forms, we record only field names and whether a value was entered. We also record the originating IP address to identify automated crawlers and the operator’s own visits and exclude them from aggregates.
Data Not Recorded by Analytics
We do not record entered content such as names, email addresses, or search terms. An anonymous browser identifier is stored in a cookie for 400 days.
Retention and aggregation
Behavioral events recorded by our own systems are deleted after 400 days. Visits believed to be automated are retained when received and separated during aggregation based on whether there was an interaction or a stay of at least four seconds.
Data sent to the operator-managed analytics server
Data is sent to analytics.hacci.dev, an analytics server managed by the operator. We send the page path, referrer, views, clicks, external-link interactions, scroll depth, and time displayed before leaving the page. Cookies are not used. To group actions from the same visit, a random identifier is stored in the browser’s session storage and replaced after 30 minutes of inactivity. Entered content and personally identifiable information are not sent. IP addresses are transformed on the server into an irreversible form and then discarded.
External transmission to Google Analytics
Data is sent to Google LLC through Google Analytics. This includes the URLs of pages viewed, referrers, browser, device and screen information, and identifiers stored in cookies. The transmitted information is used to understand and improve use of the site.
You can stop this transmission through your browser’s cookie settings or the Google Analytics Opt-out Browser Add-on provided by Google.
Advertising through Google AdSense
Ads provided by Google LLC’s Google AdSense appear at the bottom of some tower and unit pages. To deliver ads, measure performance, and prevent misuse, Google and advertising providers may use cookies, web beacons, IP addresses, and similar technologies to collect information about pages viewed, browsers and devices, and ad views and interactions. Third-party vendors may display ads based on information such as sites previously visited.
You can manage ad personalization in Google Ads Settings. See Google’s information for details on how Google uses information collected from partner sites and apps.
Embedded YouTube videos
Some tower pages embed YouTube videos. When the page opens, only the video thumbnail is loaded from YouTube’s servers (Google LLC); the YouTube player loads when you press the play button. At that time, this site’s domain name and browser and device information are sent to Google, and YouTube may use cookies and similar technologies. See Google’s Privacy Policy for information on how transmitted data is handled.
Voting, price-drop alerts, and correction submissions
For one-tap polls such as “Buy / Wait and see / Still too expensive,” we store only the anonymous browser identifier described above and your selected option. We do not store names, email addresses, or IP addresses.
If you enable browser notifications for price drops, we store the notification endpoint issued by your browser (the push-service URL), encryption keys, and selected tower. Notifications are delivered through your browser provider’s push service, such as Google, Apple, or Mozilla, and their content is encrypted between this site and your browser. This information is deleted when you disable notifications.
Information submitted as a correction or addition to tower data—the field, value, source URL, and notes—is stored for verification and publication. Only the field, value, source site name, and submission date are published. If the source is an eligible site for verification, our server retrieves the URL once to verify it.
Member profiles and owned properties
When you register a nickname, it is displayed on member posts and your profile. You may also publish an introduction, favorite areas, towers you are watching, and whether you are considering buying or selling. For portfolio units you choose to make public, only the tower name and area and the fields selected for each unit—floor, size, layout, orientation, and purchase or sale price and date—are published. Names and email addresses from sign-in information are never used as display names. Changing your nickname also changes the displayed name on past member posts. Like nicknames, introductions and favorite areas are processed only on equipment managed by this site to determine whether they may be published.
Portfolio units and valuation results are visible only to the member. Only when “Publish an overview of owned properties” is selected in profile settings are tower names, areas, and the number of registered units shown on a public profile and share card. This setting also applies to properties added later. Floors, sizes, purchase prices, valuation amounts, loan balances, and similar details are not published. You can make the information private again at any time, after which the share card will no longer appear.
When you follow a member or tower, the followed target and start time are stored with your account. Reactions and quotes of your posts, and members who follow you, appear in interaction notifications. We store only the last time you marked notifications as read.
Review and Message Board Posts
Posting requires sign-in and a public nickname. Posts are linked to your account and display your nickname and a link to your profile. To prevent repeated posting, a keyed one-way transformation of source information is stored with the post record and deleted after a set period. The IP address itself is not stored. If you submit a report without signing in, a signed identifier issued by this site is stored in a cookie for 400 days to prevent duplicate reports.
Post text, media captions, and nicknames are processed only on equipment managed by this site to determine whether they may be published. They are never sent to external providers. We record the model and criteria used, the result, and processing time. The reasoning process is not stored.
Images and videos attached to posts are not sent to external providers. Images are regenerated as WebP and videos as MP4 within this site. EXIF data, including location information, and the original images and videos are not retained. Before an image is discarded, we check only whether camera-model information and signs of image-generation tools are present; values such as model names are not retained. This is used to identify Best Photo candidates. Regenerated media is stored with the post and displayed only while the post is public. It is deleted immediately if deterministic checks reject it, the poster deletes it, or it is hidden following a report or operator action. If rejected by LLM review, it is kept private for seven days for possible re-review and then deleted.
Posting rules and procedures for requesting removal are described in the Reviews and Discussion Board Terms of Use.