diff --git a/src/libgetopts/lib.rs b/src/libgetopts/lib.rs
index b809138c45179..a5a84b22c1990 100644
--- a/src/libgetopts/lib.rs
+++ b/src/libgetopts/lib.rs
@@ -79,7 +79,7 @@
 //! ```
 
 #![crate_name = "getopts"]
-#![experimental]
+#![experimental = "use the crates.io `getopts` library instead"]
 #![crate_type = "rlib"]
 #![crate_type = "dylib"]
 #![doc(html_logo_url = "http://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
diff --git a/src/liblog/lib.rs b/src/liblog/lib.rs
index 8b79078eac6ad..498fa2b5e744c 100644
--- a/src/liblog/lib.rs
+++ b/src/liblog/lib.rs
@@ -158,7 +158,7 @@
 //! if logging is disabled, none of the components of the log will be executed.
 
 #![crate_name = "log"]
-#![experimental]
+#![experimental = "use the crates.io `log` library instead"]
 #![crate_type = "rlib"]
 #![crate_type = "dylib"]
 #![doc(html_logo_url = "http://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
diff --git a/src/libregex/lib.rs b/src/libregex/lib.rs
index b35c3879783a0..2d64aac6f7915 100644
--- a/src/libregex/lib.rs
+++ b/src/libregex/lib.rs
@@ -362,7 +362,7 @@
 #![crate_name = "regex"]
 #![crate_type = "rlib"]
 #![crate_type = "dylib"]
-#![experimental]
+#![experimental = "use the crates.io `regex` library instead"]
 #![doc(html_logo_url = "http://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
        html_favicon_url = "http://www.rust-lang.org/favicon.ico",
        html_root_url = "http://doc.rust-lang.org/nightly/",
diff --git a/src/libregex_macros/lib.rs b/src/libregex_macros/lib.rs
index 4df8819774319..11976b11c7e66 100644
--- a/src/libregex_macros/lib.rs
+++ b/src/libregex_macros/lib.rs
@@ -13,7 +13,7 @@
 
 #![crate_name = "regex_macros"]
 #![crate_type = "dylib"]
-#![experimental]
+#![experimental = "use the crates.io `regex_macros` library instead"]
 #![doc(html_logo_url = "http://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
        html_favicon_url = "http://www.rust-lang.org/favicon.ico",
        html_root_url = "http://doc.rust-lang.org/nightly/")]