diff --git a/crates/application/src/ports.rs b/crates/application/src/ports.rs
index 1b03f17..52a8604 100644
--- a/crates/application/src/ports.rs
+++ b/crates/application/src/ports.rs
@@ -1,6 +1,6 @@
 use uuid::Uuid;
 
-use domain::models::{DiaryEntry, collections::Paginated};
+use domain::models::{DiaryEntry, FeedEntry, MonthActivity, UserStats, UserSummary, UserTrends, collections::Paginated};
 
 pub struct HtmlPageContext {
     pub user_email: Option<String>,
@@ -23,11 +23,41 @@ pub struct NewReviewPageData<'a> {
     pub error: Option<&'a str>,
 }
 
+pub struct ActivityFeedPageData {
+    pub ctx: HtmlPageContext,
+    pub entries: Paginated<FeedEntry>,
+    pub current_offset: u32,
+    pub has_more: bool,
+    pub limit: u32,
+}
+
+pub struct UsersPageData {
+    pub ctx: HtmlPageContext,
+    pub users: Vec<UserSummary>,
+}
+
+pub struct ProfilePageData {
+    pub ctx: HtmlPageContext,
+    pub profile_user_id: Uuid,
+    pub profile_user_email: String,
+    pub stats: UserStats,
+    pub view: String,
+    pub entries: Option<Paginated<DiaryEntry>>,
+    pub current_offset: u32,
+    pub has_more: bool,
+    pub limit: u32,
+    pub history: Option<Vec<MonthActivity>>,
+    pub trends: Option<UserTrends>,
+}
+
 pub trait HtmlRenderer: Send + Sync {
     fn render_diary_page(&self, data: &Paginated<DiaryEntry>, ctx: HtmlPageContext) -> Result<String, String>;
     fn render_login_page(&self, data: LoginPageData<'_>) -> Result<String, String>;
     fn render_register_page(&self, data: RegisterPageData<'_>) -> Result<String, String>;
     fn render_new_review_page(&self, data: NewReviewPageData<'_>) -> Result<String, String>;
+    fn render_activity_feed_page(&self, data: ActivityFeedPageData) -> Result<String, String>;
+    fn render_users_page(&self, data: UsersPageData) -> Result<String, String>;
+    fn render_profile_page(&self, data: ProfilePageData) -> Result<String, String>;
 }
 
 pub trait RssFeedRenderer: Send + Sync {
diff --git a/crates/application/src/queries.rs b/crates/application/src/queries.rs
index 8619b05..b4898f0 100644
--- a/crates/application/src/queries.rs
+++ b/crates/application/src/queries.rs
@@ -11,3 +11,17 @@ pub struct GetDiaryQuery {
 pub struct GetReviewHistoryQuery {
     pub movie_id: Uuid,
 }
+
+pub struct GetActivityFeedQuery {
+    pub limit: Option<u32>,
+    pub offset: Option<u32>,
+}
+
+pub struct GetUsersQuery;
+
+pub struct GetUserProfileQuery {
+    pub user_id: Uuid,
+    pub view: String,
+    pub limit: Option<u32>,
+    pub offset: Option<u32>,
+}
diff --git a/crates/application/src/use_cases/get_activity_feed.rs b/crates/application/src/use_cases/get_activity_feed.rs
new file mode 100644
index 0000000..afee970
--- /dev/null
+++ b/crates/application/src/use_cases/get_activity_feed.rs
@@ -0,0 +1,13 @@
+use domain::{
+    errors::DomainError,
+    models::{FeedEntry, collections::{PageParams, Paginated}},
+};
+use crate::{context::AppContext, queries::GetActivityFeedQuery};
+
+pub async fn execute(
+    ctx: &AppContext,
+    query: GetActivityFeedQuery,
+) -> Result<Paginated<FeedEntry>, DomainError> {
+    let page = PageParams::new(query.limit, query.offset)?;
+    ctx.repository.query_activity_feed(&page).await
+}
diff --git a/crates/application/src/use_cases/get_user_profile.rs b/crates/application/src/use_cases/get_user_profile.rs
new file mode 100644
index 0000000..9ad587d
--- /dev/null
+++ b/crates/application/src/use_cases/get_user_profile.rs
@@ -0,0 +1,91 @@
+use domain::{
+    errors::DomainError,
+    models::{
+        DiaryEntry, DiaryFilter, MonthActivity, SortDirection, UserStats, UserTrends,
+        collections::{PageParams, Paginated},
+    },
+    value_objects::UserId,
+};
+use crate::{context::AppContext, queries::GetUserProfileQuery};
+
+pub struct UserProfileData {
+    pub stats: UserStats,
+    pub entries: Option<Paginated<DiaryEntry>>,
+    pub history: Option<Vec<MonthActivity>>,
+    pub trends: Option<UserTrends>,
+}
+
+pub async fn execute(
+    ctx: &AppContext,
+    query: GetUserProfileQuery,
+) -> Result<UserProfileData, DomainError> {
+    let user_id = UserId::from_uuid(query.user_id);
+    let stats = ctx.repository.get_user_stats(&user_id).await?;
+
+    match query.view.as_str() {
+        "history" => {
+            let all_entries = ctx.repository.get_user_history(&user_id).await?;
+            let history = group_by_month(all_entries);
+            Ok(UserProfileData { stats, entries: None, history: Some(history), trends: None })
+        }
+        "trends" => {
+            let trends = ctx.repository.get_user_trends(&user_id).await?;
+            Ok(UserProfileData { stats, entries: None, history: None, trends: Some(trends) })
+        }
+        "ratings" => {
+            let page = PageParams::new(query.limit, query.offset)?;
+            let filter = DiaryFilter {
+                sort_by: SortDirection::ByRatingDesc,
+                page,
+                movie_id: None,
+                user_id: Some(user_id),
+            };
+            let entries = ctx.repository.query_diary(&filter).await?;
+            Ok(UserProfileData { stats, entries: Some(entries), history: None, trends: None })
+        }
+        _ => {
+            // "recent" (default)
+            let page = PageParams::new(query.limit, query.offset)?;
+            let filter = DiaryFilter {
+                sort_by: SortDirection::Descending,
+                page,
+                movie_id: None,
+                user_id: Some(user_id),
+            };
+            let entries = ctx.repository.query_diary(&filter).await?;
+            Ok(UserProfileData { stats, entries: Some(entries), history: None, trends: None })
+        }
+    }
+}
+
+fn group_by_month(entries: Vec<DiaryEntry>) -> Vec<MonthActivity> {
+    use std::collections::BTreeMap;
+    let mut map: BTreeMap<String, Vec<DiaryEntry>> = BTreeMap::new();
+    for entry in entries {
+        let ym = entry.review().watched_at().format("%Y-%m").to_string();
+        map.entry(ym).or_default().push(entry);
+    }
+    let mut result: Vec<MonthActivity> = map
+        .into_iter()
+        .map(|(ym, entries)| MonthActivity {
+            month_label: format_year_month_long(&ym),
+            count: entries.len() as i64,
+            entries,
+            year_month: ym,
+        })
+        .collect();
+    result.reverse();
+    result
+}
+
+fn format_year_month_long(ym: &str) -> String {
+    let parts: Vec<&str> = ym.splitn(2, '-').collect();
+    if parts.len() != 2 { return ym.to_string(); }
+    let month = match parts[1] {
+        "01" => "January", "02" => "February", "03" => "March", "04" => "April",
+        "05" => "May", "06" => "June", "07" => "July", "08" => "August",
+        "09" => "September", "10" => "October", "11" => "November", "12" => "December",
+        _ => parts[1],
+    };
+    format!("{} {}", month, parts[0])
+}
diff --git a/crates/application/src/use_cases/get_users.rs b/crates/application/src/use_cases/get_users.rs
new file mode 100644
index 0000000..2efd6e4
--- /dev/null
+++ b/crates/application/src/use_cases/get_users.rs
@@ -0,0 +1,9 @@
+use domain::{errors::DomainError, models::UserSummary};
+use crate::{context::AppContext, queries::GetUsersQuery};
+
+pub async fn execute(
+    ctx: &AppContext,
+    _query: GetUsersQuery,
+) -> Result<Vec<UserSummary>, DomainError> {
+    ctx.user_repository.list_with_stats().await
+}
diff --git a/crates/application/src/use_cases/mod.rs b/crates/application/src/use_cases/mod.rs
index 63da43b..8f8bdb7 100644
--- a/crates/application/src/use_cases/mod.rs
+++ b/crates/application/src/use_cases/mod.rs
@@ -1,6 +1,9 @@
 pub mod delete_review;
+pub mod get_activity_feed;
 pub mod get_diary;
 pub mod get_review_history;
+pub mod get_user_profile;
+pub mod get_users;
 pub mod log_review;
 pub mod login;
 pub mod register;